Magnetic nanostructures and devices possess unique features that qualify them for a broad range of scientific and industrial applications. These features directly result from their small size that allows chemical binding to DNA and molecules, ultra high device integration, ultrafast precessional magnetization reversal observable in nanosize monodomain structures, and all-electrical spin-torque switching at high current densities. The exploitation of these features requires reliable measurement tools specifically adapted to magnetic nanostructures.

The main goal of the NanoSpin project was to establish a metrological basis for the study of nanometer sized magnetic structures and devices. These novel types of materials are important for their expected social and economic impact as they are being employed in a larger and larger number of applications ranging from biomedical, communication/information technology, environmental protection and monitoring devices. These new developments require reliable measurement tools to characterize the magnetic nanomaterials used and embedded with a verified traceability to existing standards. To this end, the project was designed to deliver measurement methods and reference samples for industrial stakeholders and scientific partners.

Identify key achievements

Management

- Effective cooperation was established for all the activities involving deliverables.

- All personnel issues were positively solved at INRIM, LNE and NPL. Financial issues of PTB were dealt with by EMRP and new budget tables derived.

- After a budget revision in October 2010, additional resources were allocated for a positive conclusion of the project.

- The cooperation established during the project was successful in attracting additional funding for the ensuing development of application oriented activities.

Scientific activities

· A specific workpackage (WP2) Reference Nanomaterials was associated to the production and patterning of reference materials and structures, with deliverables every six months from the JRP start. Within this WP a large number of reference samples and structures were either produced or procured, characterized and customized for use by the ensuing WPs.

- NiFe thin films were integrated in CoPlanar Waveguides for time/frequency domain dynamics experiments.

- GaMnAs Diluted Magnetic Semiconductor samples were produced and characterized for precessional dynamics.

- Size Monodispersed Magnetic NanoParticles were produced for high resolution scanning probe microscopy and ultra sensitive magnetic moment detection.

- Hard magnetic materials with out-of-plane anisotropy were patterned for high resolution scanning probe microscopy.

· In the WP3 Time and frequency domain dynamics traceable inductive and magneto transport measurements have been established. Standard procedures for the characterization of different types of materials and devices have been derived using reference samples.

- Validated inductive metrology of ferromagnetic resonance frequency f_FMR and the damping constant parameter α was established.

- A set of calibrated reference samples is available for inductive measurements of f_FMR and α by industrial and academic partners (Tohoku University, Bielefeld University, Singulus A.G.)

- Metrology for the Spin Torque precession of nanodevices was established in the time and frequency domain

- New techniques for the detection precession in GaMnAs samples at low temperature were established using magneto optic detection schemes.

· WP4 High Resolution Scanning Probe Microscopy was focused to the development and technological dissemination of a quantitative and traceable MFM imaging technique of magnetic fields and magnetization distributions. Appropriate software and hardware tools were developed correctly implemented.

- Quantitative Magnetic Force Microscopy metrology with resolution < 50 nm was demonstrated using magnetic nanoparticles and notable results were obtained using a CoPt sample with a maze-like domain structure.

- A tuning fork microscope with 100 nm spatial resolution was developed and tested for operation at liquid Helium temperature.

· In the WP5 on Ultra sensitive magnetic moment detection one of the key outcomes was a nano-SQUID system with improved sensitivity allowing direct measurements of the magnetic moment of individual magnetic nanoparticles and nanoobjects with a diameter or one dimension down to 10 nm. Another outcome was related to the development of a nanosized Hall sensor.

- A nano-SQUID detector with sensitivity µ_min ~ 10²µ_B/√Hz at LT temperature was tested (N_spins~ 10 m_B/ÖHz)

- Nanosized metallic and semiconductor (2DEG heterostructures) Hall sensors with lateral dimensions below 500 nm have been characterized and tested.

- A nanosized Hall-sensor detector with a sensitivity better of 10⁶µ_B (N_spin~1300 m_B /ÖHz) has been demonstrated at RT.

· In the WP 6: Dissemination, Exploitation and Knowledge Transfer activities several outcomes were achieved:

- For dissemination a large number of scientific publications, conference presentations and talks in companies and institutions were given by the project partners (full listing at www.nanospin.eu).

- For the exploitation and future developments of the activities a Dissemination Meeting and Euramet EM DC & Quantum Metrology Experts Meeting was jointly organized and attended in May 2011 in Berlin. The NanoSpin project has found a natural path to industrial development with the approval of the subsequent EMRP art. 169 project “Metrology for Advanced Industrial Magnetics” which started on July 1^st 2011. At the moment the largest market associated to NanoSpin activities is connected to the production of anisotropic magnetoresistive and Hall sensors for a wide range of applications in the automotive, consumer electronics, communications, industrial, aerospace and defence markets. This is a rather mature technology where the impact of our project is small but not negligible, in fact a new application oriented project is being started in this area (Metrology for Advanced Industrial Magnetics). Also novel magnetic memory applications such as MRAM, ST-RAM and are being considered for production by Singulus AG, Everspin and Samsung. The method developed within the Consortium for accurate measurements of Hall sensors in ambient conditions and separation of measurement artifacts has been successfully transferred to stakeholders. Finally there is an increasingly widespread use of magnetic nanoparticles in the biomedical sector, where the project has been able to provide specific measurement and calibration techniques. These techniques are being currently used for smaller project with a startup and another smaller company in Italy and for a new proposal with a large number of stakeholders in the biomedical field.

- Concerning Knowledge transfer, several joint activities were established:

o Univ. of Duisburg, Trinity College Dublin , University College Cork, Univ. of Vienna – development and characterization of reference nanomaterials

o Imperial College London, Cambridge Univ., Surrey Univ. - sensor fabrication, nanomanipulation of magnetic nanoparticles

o TU Chemnitz, Hitachi GST and the CNR IMEM Parma: preparation of Hard magnetic thin films for hard magnetic reference samples.

o Tohoku University, NIST Boulder, University of Colorado, Northeastern University Boston: Application of novel techniques for Ferromagnetic resonance and damping for microwave applications

o Singulus AG, University of Bielefeld, NIST Boulder Collaborators in the study of the dynamics of Tunneling Magnetic Junctions and point contacts for memory/sensor applications

o TU Chemnitz, Hitachi GST, University of Parma, University of Göttingen, IFW Dresden TU Braunschweig, Magnicon GmbH : High resolution magnetic microscopy/MFM calibration

o Samsung Technologies will visit PTB in July 2011 to discuss exploitation of results in the field of ultra fast dynamics of ST MRAM.

2. Project context, rationale and objectives

2.1 INtroduction

In the field of nanomagnetism and spintronics, new developments are under way in applications ranging from ultra strong magnets, spin polarized materials, ultra high density recording media, spin transistors, spin-based qubits, leading to potential mass market products such as the instant boot computer, computer in a test tube and ubiquitous DNA- and bio-sensors. All these developments and potential mass markets urgently require measurement tools to reliably characterize magnetic nanomaterials and structures with verified traceability to existing standards: to date there are very few producers of magnetic nanostructures and nanomaterials who are able to provide them. The value of the project NanoSpin is thus associated to the development of magnetic measurement techniques and materials at the frontier of current technical capabilities, which are under fast development and industrial exploitation in Europe and worldwide. It is expected that the project NanoSpin will be able provide reference samples, measurement methods and services to industry and academia.

2.2 proposal CONTEXT

The future of Europe in an increasingly integrated and globalized market cannot rely on low-technology content products. New ideas with high potential must be explored to exploit existing markets and foster new developments in fields with high scientific value and strong technological impact. To this end, the overall goal of the NanoSpin project is to establish a metrological basis for the characterization of nanometer sized magnetic structures and devices. These structures and devices will have a huge social and economic impact, being the key ingredient in a wide range of existing and future applications in the biomedical field (drug delivery, DNA detection/extraction, cancer treatment), in information technologies (computer memories, MRAM), and in environmental protection and monitoring (air and water pollution reduction, chemical and biochemical sensing).

The potential economic impact of the NanoSpin project can be estimated from the worldwide market value of nanotechnology-enabled products worth over 2.5 10¹⁰ € in 2005 and with a projected value of 1.1 10¹² € in 2015, a sum comparable to the telecom market value today of 6.9 10¹¹ €. Over 350 products containing nanomaterials were on the market in 2005 especially exploiting enhanced chemical/physical properties resulting from reduced size. The global market for nanoparticles used in electronic, magnetic, and optoelectronic applications increased from $499.7 million in 2006 to an estimated $521.9 million in 2007. It should reach $1100 million by 2012, with a compound annual growth rate of 16.5%. In the field of nanomagnetism, exciting new developments are under way in applications ranging from ultra strong magnets, spin polarized materials, ultra high density recording media (hard disks, flash memories/MRAM), spin transistors, spin-based qubits, leading to potential mass market products such as the instant boot computer, computer in a test tube and ubiquitous DNA- and bio-sensors. All these developments and potential mass markets urgently require measurement tools to reliably characterize magnetic nanomaterials and structures with verified traceability to existing standards4: to date there are very few producers of magnetic nanostructures and nanomaterials who are able to provide them. Such traceability is also indispensable for a sound risk assessment of nanomaterials e.g. in the health sector.

The value of the project NanoSpin is thus associated to the development of magnetic measurement techniques and materials at the frontier of current technical capabilities, which are under fast development5 and industrial exploitation6 in Europe and worldwide. It is expected that the project NanoSpin will be able provide reference samples, measurement methods and services to industry and academia. In this respect, significant impact can only be expected from a joint European-level effort as the individual National Metrological Institutes (NMI) do not separately posses the technical capabilities and financial resources required to develop all the enabling technologies necessary to establish a metrology for nanomagnetism: these include production and characterization of different types of magnetic nanoparticles, thin films and nanostructures of different degrees of complexity. Nanotechnology can be developed with two approaches: a lower cost, bottom up approach, which exploits self assembly, biochemistry and inorganic chemistry techniques; and a much more costly top down approach, based on brute force electron beam or focused ion-beam lithography which is currently dominated by industry and large consortia. While the development of nanosized structures such as nanopowders or nanocolumnar arrays can be accomplished at a relatively low cost, no low cost techniques are currently available for imaging or measuring the physical and electromagnetic properties of nanomaterials. In this respect the activities associated to metrology for nanotechnology were defined among the Grand Challenges for multidiscipline metrology of the EMRP scheme.

The NanoSpin project is especially focused on both the dimensional/magnetic analysis of nanostructured materials using scanning probe microscopy techniques, and on the magnetic and electromagnetic characterization of nanosized structures associated to the development of devices that utilize spin polarized currents, such as MRAM and point contact microwave frequency oscillators. Exploitation of the results will proceed mainly through the contacts with the scientific and industrial stakeholders involved in activities associated to the NanoSpin project.

2.3 proposal rationale and objectives

The objective of this Joint Research Project was to establish a sound metrology for the field of nanomagnetism with respect to the three key aspects of nanomagnetic measurements: nanoscale imaging, ultrafast dynamics, and detection of ultra-small magnetic signals. These three main aspects were covered by three scientific work packages: imaging, magnetization dynamics, and magnetic moment detection. For these WPs well-characterized materials and samples were essential, since they allowed for the comparison of measurements, for the validation of the results through sample exchange or were directly involved in traceability chains. Therefore the WP reference nanomaterials was an essential part of the project.

Reference nanomaterials designed and fabricated or obtained from external partners within this WP necessarily covered a broad span of different characteristics and properties due to the different needs of the ensuing scientific WPs. Reliable MFM calibration samples can only be fabricated from hard magnetic materials, reference materials for imaging or magnetic moment measurements require ultra small structures down to 10 nm diameter and below which can be obtained using self-assembled nanostructures. Reference samples for validation of magnetization dynamics are typically soft magnetic nm-thin films having lateral dimensions of several μm and in some cases specific nanopatterns. As a consequence, a broad range of technological skills and competences are required for the fabrication of such structures. Among them are the growth of high quality magnetic thin films, top down patterning using electron beam or focused ion beam lithography and clean room processing and bottom up fabrication of ultra small magnetic particles by self assembly. These combined and complementary competences are present in the four participants of the WP materials INRIM, NPL, PTB, and LNE. Specific fabrication and technology intensive processing steps will be performed by specific partners of each institution.

2.3.1 State of the art

Nanopowders of different nominal sizes and size distributions can be found on the market but they are rarely delivered with a characterization sufficient for strictly scientific let alone metrological purposes. Micropatterned films and artefacts can be obtained from producers of microscopy equipment (with patterns whose dimensions are traceable to NIST), scientific institutions and industrial stakeholders, but currently there are no companies which are able to provide reference nanopatterns, not to mention magnetic patterns of any type. This is due to the intrinsic cost of production and scientific difficulty of characterization at the nanosize level of structural and magnetic features.

Magnetic imaging tools with nanometer spatial resolution are required to determine the static magnetic properties of nanomagnetic materials and devices. The imaging tools need to be complemented by dynamic measurement techniques capable of detecting precessional magnetization dynamics down to the picosecond time scale. The small size of the magnetic nanostructures inevitably implies that magnetic moments and electro-magnetic signals in general are extremely weak. As a consequence, the sensitivity of the measurement tools needs to be pushed to the utmost limit, and one notable example is the detection of the magnetic moment of individual nanostructures at the level of few to a single Bohr magneton μ_B. Phase contrast TEM, spin polarized STM, X-ray magnetic imaging and MFM allow for nm scale imaging of magnetic domain structures. But among these techniques only MFM is sufficiently versatile, fast, and robust for industrial production line testing and characterization. Detection of small magnetic moments can be achieved using SQUID and Hall sensors. Ultrafast magnetization dynamics is accessible in the time and frequency domain using magneto optics, inductive methods and magneto transport. Yet, these methods lack a sound metrological basis characterized by traceability, detailed uncertainty budgeting, and validation procedures.

3. Scientific and technological results and foreground

3.1 wp Reference nanomaterials

This WP was focused on the design and fabrication of nanopatterned/nanostructured soft and hard magnetic reference materials, films and multilayers according to the needs of the ensuing WPs. Characterized reference materials were made available to partners and collaborators to disseminate and exploit the results of this JRP. The WP has achieved the necessary deliverables on schedule.

3.1.1 Soft magnetic samples

Permalloy is the alloy most applied in high frequency applications, including write and read heads for hard disks. The study of Permalloy is at the base of a wide variety of high frequency applications.

Permalloy (Ni₈₀Fe₂₀) thin films were produced characterized and integrated integrated in Coplanar Waveguides for time/frequency domain dynamics experiments. The soft magnetic reference materials/patterns were developed for ferromagnetic resonance and Gilbert damping α measurements.

• Production and distribution of NiFe thin films of different thickness 10-30 nm

• Clean room fabrication of soft magnetic reference samples with integrated patterned magnetic thin films.

• Variation of sample geometry (position, width and length of magnetic pattern, and of coplanar wave guide).

HWS

Figures: Coplanar wave schematic (left), design (center) and realized sample with multiple patterned waveguides with different geometries of the Permalloy samples (right)

3.1.2 Nanopillars/nanocontacts

Magnetic Tunnel Junction pillars, produced by Singulus AG were obtained for spin torque dynamics experiments. Point contact samples, also for spin torque dynamics experiments were obtained from NIST and IMEC. The extremely small size is necessary to achieve the current densities required to observe spin torque effects.

Example of Nanopillar MTJ structure (Nature Mat. doi:10.1038/nmat2804) (left) and nanosized point contact structure (courtesy of NIST Boulder) (right)

3.1.3 Diluted Magnetic Semiconductor samples for precessional dynamics

Gallium manganese arsenide is a magnetic semiconductor, based on GaAs. Differently from other DMS systems it is ferromagnetic, an essential property for potential use in memory devices. In (Ga,Mn) As, the manganese atoms provide a magnetic moment, and makes it a p-type material: the presence of charge carriers and ferromagnetism also allows the material to be used for the transport of spin-polazed currents. GaMnAs ferromagnetic semiconductor thin films samples were produced by Molecular Beam Epitaxy as single o trilayer at PTB.

Figure: GaMnAs Scanning Tunnel Microscopy topography of the in-gap states of GaMnAs (DOI: 10.1126/science.1183640)

3.1.4 Hard magnetic materials

Patterns of hard magnetic materials with anisotropy perpendicular to the film plane are considered on of the best systems for the development of reference magnetic samples for high resolution scanning probe microscopy. Several samples were obtained from different sources:

- CNR-IMEM Parma Production of FePt films by sputtering

- Politecnico di Milano Production of CoPt films by electrodeposition

- Hitachi GST Research Center S. Jose Ca, Production of FePt films by sputtering

- TU Chemnitz hard magnetic films

The materials were then properly patterned by NPL and PTB, with a range of different processes. Regardless of the efforts, the final structures were not stable, and magnetic contrast was lost after a few days/weeks time. It was anyhow shown that magnetic nanoparticles could replace the hard materials to achieve the declared project goals.

Deliverable 2.3: Fabrication and characterization of a set of hard magnetic reference structures for magnetic imaging June 2009-2010-2011.

3.1.5 Magnetic Nanoparticles

One of the simplest systems with great potential in nanomagnetic applications is based on Fe oxide nanoparticles. Size monodispersed magnetic nanoparticles were produced for high resolution scanning probe microscopy and ultra sensitive magnetic moment detection. The production and characterization of magnetic nanoparticles was performed at INRIM, Trinity College, University of Duisburg.

Figure: High resolution transmission electron microscopy image (500.000x) of Fe oxide nanoparticles of 13 nm average size (Dip.di Chimica IFM Torino University).

3.2 WP 3: Time and frequency domain dynamics

SUMMARY

This WP was focused on the metrology of microwave measurements of nanomagnetic devices in time and frequency domain. Inductive time and frequency domain metrology for f_FMR and a of soft magnetic thin films

3.2.1 Inductive time and frequency domain metrology for f_FMR and a of soft magnetic thin films

Sketch of integrated coplanar wave guide (CPW) reference samples. CPW concutor includes two ground (G) and one signal (S) line. CPW conductor: orange; patterned magnetic film: green; substrate grey. The width of the magnetic film W_M = 10 … 85 µm is varied.

In this task inductive metrology of the ferromagnetic resonance frequency f_FMR and the Gilbert damping a of soft magnetic thin films was established and validated. Text Box:
Figure 3.2.1a: Comparison of inductive measurements of precession frequency in time and frequency domain of integrated reference samples with different stripe width. Data is offset for clarity. Time (triangles) and frequency (squares) data show very good agreement and can be described by a Kittel model with demagnetization factors adapted to the sample geometry (lines).

A comparison of a for the same set of reference samples is shown in Figure 3.2.2 The values of alpha have again been derived independently by PIMM and VNA-FMR measurements. Over a broad range of sample geometries the damping values derived from time and frequency domain measurements agree well within the measurement uncertainty. The uncertainty is again dominated by the uncertainty of the fit to the measured data. In addition to the VNA measurements also field dependent microwave absorption measurements at fixed frequency have been performed at INRIM leading to comparable results (not shown).

The two comparisons of Fig. 3.2.1a and 3.2.1b show that a validated inductive metrology of f_FMR and a of has been established. Furthermore, a set of calibrated soft magnetic reference samples is available for external inductive measurements of f_FMR and a.

Text Box:
Figure 3.2.1b: Comparison of inductive measurements of the effective Gilbert damping a of integrated reference samples with different stripe width. Data deduced from time domain (triangles) and frequency domain (squares) measurements generally agrees well within the measurement uncertainty for a broad range of sample geometries.

3.2.2 Magneto transport metrology schemes for dynamics of individual spin transfer torque nano devices

In this task magneto transport metrology schemes for detection of spin torque precession in individual magnetic nanodevices were developed and established.

At PTB a magneto transport experiment for time resolved measurement of spin torque (ST) dynamics of individual magnetic tunnelling junction nanopillars have been used for further characterization of ST dynamics of CoFeB/MgO based magnetic tunnelling junction (MTJ) nanopillars. The setup for time resolved dynamics measurements is shown in Figure 3.2.1a (bottom).

A pulse from a fast pulse generator induces precession in the MTJ nano pillar. The resulting ST precession is detected by an oscilloscope via the tunnelling magneto resistance (TMR) change using a dc probe current. The advantage of this setup compared to other setups as described in the literature is that both the ST precession during application of a current pulse as well as the free precession after the decay of the ST pulse can be detected. This enables a detailed analysis of the changes on the effective damping due to ST precession.

Text Box:
Figure 3.2.2a: Measurement setups for frequency domain (top) and time domain (bottom) metrology for dynamics of individual spin transfer torque nano devices.

A typical measurement of free and ST precession is shown in Figure 3.2.1b. The top panel shows free precession as excited by a 100 ps ST pulse. The bottom panel shows ST precession during a 5 ns ST pulse. From the data a and f_FMR is be derived by fitting the precession signal by a damped sinusoid. During the reporting period the ST precession parameters have been studied in detail as function of field and ST parameters (static field amplitude H_S, static field angle phi, current density j).

Furthermore different noise measurements of ST precession have been carried out at INRIM and at PTB. A sketch of the setup is shown in Figure 3.2.1b (top). A dc current is applied to a nanodevice (either a spin valve point contact or a MTJ nanopillar) inducing ST precession. Due to magneto resistance of the ST nano device the ST precession is converted into a characteristic peak at the precession frequency in the frequency power spectrum. From the peak position and the linewidth of the ST precession f_FMR and a can be derived.

Using this frequency domain setup a set of five MTJ nanopillars has been by characterized at PTB. The analysis of the ST precession parameters is ongoing.

Text Box:
Figure 3.2.2c: Frequency domain signal associated to spin torque oscillations induced by dc current in a 40 nm diameter point contact magnetized at 80° out of plane with a bias field of 0.8T At INRIM the activity was focused on a set of point contact samples obtained from NIST Boulder (See Figure 3.2.1c). The activity was directed to the characterization of the noise behaviour induced by dc current injection under the influence of an intense magnetic field applied at different angles with respect to the film plane. The data shows several interesting points. Depending on the contact characteristics, and the spin-dependent scattering conditions, a dc current may be able to produce a noise signal in the microwave regime with very narrow linewidth (i.e. 10 MHz at 13 GHz) for a wide range of applied currents. On the contrary a lower applied field may produce linewidths of the order of 1 GHz. A mapping is shown in the following figures. The frequency and linewidth mapping of this noise behaviour is the essence of the characterization of these systems for future application development.

3.2.3 Low temperature inductive time and frequency domain metrology for magnetization dynamics of diluted ferromagnetic semiconductors

In this task metrology for the precessional dynamics of low magnetic moment diluted magnetic semiconductors (DMS) was established.

A 3D vector magnet cryostat system (1T vector field) for measurements of low temperature inductive magnetization dynamics has been installed at PTB during the previous reporting period. In the present period inductive low temperature measurements have been validated using inductive reference samples characterized earlier within task 3.1.

Time resolved magneto optical metrology has been established at PTB. This metrology setup is based on a modified electro optical sampling experiment based on a fs laser setup. This setup is regularly used for electro optical sampling of ultra fast electrical signals by measuring the time resolved Faraday rotation. It is applied e.g. for the rise time calibration of high frequency electronics up to 110 GHz band width and for the investigation of optically induced currents.

The experiment relies on a pulsed TiSa-Laser with pulse width of 150 fs, wave length of 800 nm, and repetition rate of 75 MHz. For the magneto optical experiments a cryostate with optical access and temperature range of T = 1.5 … 300 K was introduced into the optical path.

Text Box:
Figure 3.2.3a Top: Principle of magneto optical Kerr effect. The orientation of M is derived from the Kerr rotation of the polarization of the reflected light. Bottom: Time resolved sampling of polarization rotation due to precession of M of GaMnAs at T = 4 K. Fitting allows to derive a and fFMR as given in the table. The principle of magneto optical Kerr effect is sketched in Fig. 3.2.3a, top. A linearly polarized light that is reflected from a magnetic film is subject to a Kerr rotation theta of the polarization. Time domain sampling of the Kerr rotation (i.e. of the rotation of the polarization of the reflected light) allows the detection of ultra fast magnetization precession after excitation by the pump pulse. The magneto optical sampling setup was validated by measuring the magnetization precession of epitaxial Fe thin films grown on MgO. The FMR properties spectra of these films have been inductively characterized beforehand using the inductive metrology established in the above task devoted to Soft magnetic samples.

3.3 WP 4: High Resolution Scanning Force Microscopy

The aim of the work package High Resolution Scanning Probe Microscopy was to provide methods for reliable and traceable measurements of the magnetization and the magnetic stray field of magnetic nano-structures. Two complementary approaches were pursued: quantitative magnetic force microscopy (Task 1) und scanning Hall microscopy (Task 2). To extend the applicable temperature range, for quantitative a MFM a low-temperature SPM is set up (Task3).

The original approach for providing quantitative MFM was based on a transfer function approach using a patterned a hard magnetic film. An inversion algorithm that allows for a calculation of the sample magnetization from the measured stray field data was given. An optimized reference pattern with a flat Fourier spectrum was determined by a numerical search algorithm. However, the realisation of the patterning proved to be difficult. Although hard magnetic films samples from 4 different suppliers (Hitachi, University of Parma, TU Chemnitz, piece of a hard disk) were used and 2 different patterning approaches (FIB, e-beam lithography + ion beam etching) were adopted, no satisfying results could be achieved. The main problems are a rapid degradation of the films after the FIB patterning and the edge quality after the sputter etching, respectively.

Therefore, to provide quantitative MFM during the duration of the project, two approaches were pursued: (i) a calibration approach based on a magnetic nanoparticle sample was implemented, (ii) a CoPt sample with a maze-like domain structure was provided in the frame of a cooperation with the IFW Dresden. The internal domain pattern can serve as reference structure for a transfer function based calibration approach.

i) a calibration approach based on a magnetic nanoparticle

For our present measurement setup the value of magnetic moment to be reliably resolved is limited by the resolution of our instrument corresponding to a frequency shift of 0.5 Hz. With a tip with a calibration factor of c(h=60nm) = (0.72±0.19) A×nm²/Hz, as it has been determined above, the minimum magnetic moment that can be resolved is 0.36 Anm².

Fig. 3.3a: MFM image (a) and line scan through a single MNP (b). The linescan is evaluated in SI units of the magnetic moment. The data have been smoothed and the solid line is a Gaussian profile.

To summarize, a traceable MFM technique based on a magnetic nanoparticle reference sample could be established. A spatial resolution of 20 nm was achieved. The miminum magnetic moment resolvable is 0.36 Anm² = 3.8·10⁴ µ_B.

II) MFM calibration based on a CoPt reference sample with maze-like domain pattern

In parallel to the above described work, PTB continued to work on the transfer function based calibration approach. The main issue that had to be dealt with was the difficulty to prepare nanopatterned hard magnetic samples with the required quality. Currently PTB is working on providing alternate preparation routes. However, to provide a short-term alternate solution without departing from the transfer function approach, hard magnetic thin films with a maze-like domain structure were considered as reference samples. Such samples show a Fourier spectrum similar to the Fourier spectrum of the optimized artificial reference sample developed in the frame of this project. They can be used for a transfer function based calibration using the already developed algorithms. However, an additional fitting step is required due to the fact that the domain structure of the measured samples is not known a priori but has to be extracted from the MFM image. This requires at first image processing to obtain a good guess of the domain pattern, followed by a numerical optimization.

Fig. 3.3b: MFM calibration scheme for a first order estimation of the Instrument calibration function.

If a sample with a native domain pattern is used for the calibration, another problem has to be overcome. The domain pattern is not known a priori and hence the stray field cannot be calculated. However, since the magnetization of the calibration sample is perpendicular to the sample plane, in first approximation the up direction can be distinguished from the down direction by a discrimination level for the phase shift. This results in a first guess for the domain pattern of the sample

Based on these considerations, the calibration scheme shown in Fig. 3.3b was implemented. It allows for a first order calibration of the MFM tip. The results can be improved by an iterative process based on the assumption, that a deconvolution of the MFM measurement with the previously determined ICF allows for a better guess of the domain pattern. In the normal case this iterative procedure converges. A second possibility for improvements is to vary the parameters of the inverse filtering to obtain self consistency. Both procedures will be implemented.

Similar data processing algorithms essentially have been implemented by the group of Volker Neu, IFW Dresden. Therefore, a cooperation with this group was established. Furthermore, a suitable reference sample (supplier: Olaf Hellwig, Hitachi) was provided by this group

3.3.1 Scanning Hall Microscopy

Hall sensors with noise characteristics and dimension of the Hall cross (500X500 µm²) suitable for high resolution magnetic imaging at RT were prepared. Some sensors have been designed for imaging with long leads. See next sections.

3.3.2 LT-MFM based on a tuning fork Z-sensor

After final optimization steps a LT MFM based on a tuning fork sensor operating in tapping mode was established. The tuning fork microscope with 100 nm spatial resolution was developed and tested for operation at liquid Helium temperature. (see figure)

Sensitivity mapping (self portrait) of a 2.5x2.5 um Hall sensor performed using the tuning fork microscope, using local magnetic field from an MFM probe.

3.4 Ultra sensitive magnetic moment detection

In the WP on one of the key outcomes was a nano-SQUID system with improved sensitivity allowing direct measurements of the magnetic moment of individual magnetic nanoparticles and nanoobjects with a diameter or one dimension down to 10 nm. Another outcome was related to the development of a nanosized Hall sensor.

3.4.1 NanosquidS

The partners achieved a significant progress on understanding of underlying physics of nano-SQUID and optimization of their performance. Based on the performance even of our standard nano-SQUIDs the calculated spin sensitivity is Nspins ~ 10 m_BÖHz, i.e. 10 times better than the value expected at the onset.

DSC03051_AR

Cold stage of the measurement probe stick

Fig2

Coil system with outer solenoid, inner nano-SQUID working point coils and nano-SQUID chip holder as inset.

3.4.2 Fabrication and characterization of Hall bar sensors

- Nanosized metallic and semiconductor (2DEG heterostructures) Hall sensors with lateral dimensions below 500 nm have been characterized and tested.

- A nanosized Hall-sensor detector with a sensitivity better of 10⁶µ_B (N_spin~1300 m_B /ÖHz) has been demonstrated at RT.

Three Hall crosses etched in the PicoGiga heterostructure R287A (with surface area 500 nm x 500 nm and 1 µm x 1 µm). Above, noise spectra at room temperature.

Single particle detection with nano-Hall sensor: Manipulation of a120 nm-FePt nanobead with moment ~10⁷ µ_B,and its positioning on top of 600-nm wide InSb Hall sensor.

Among these materials InSb devices demonstrated the best performance. In particular, the high-resistance 600-nm device demonstrated the Nspin~1300 m_B/ÖHz at f~1 kHz (i.e. ~100 better than targeted). Detection and susceptibility measurements of a smallest paramagnetic bead (120 nm, ~10⁷ m_B) at room temperature were performed.

"Foreground Intellectual Property" includes Intellectual Property arising from the research and development undertaken within this project after the date of signature of this agreement whether generated by one Party or two or more Parties jointly.

4. Actual and potential impact

The value of the project NanoSpin is associated to the development of magnetic measurement techniques and materials near the frontier of current technical capabilities. This area is under fast development and industrial exploitation in Europe and worldwide. NanoSpin has been so far able to provide basic reference samples and measurement methods to industrial and academic stakeholders.

The NanoSpin project was especially focused on:

- the dimensional and magnetic analysis of nanostructured materials using scanning probe microscopy techniques,

- the magnetic and electromagnetic characterization of nanosized structures associated to the development of devices that utilize spin polarized currents, such as MRAM and point contact microwave frequency oscillators.

- Exploitation of these results has been conducted mainly through the contacts with the scientific stakeholders directly involved in the activities and industrial stakeholders involved in activities associated to the NanoSpin project.

• Reference samples and measurements techniques have been developed and transferred to partners.

• A large number of related papers (~40) were published, many conference presentations were made. See website (www.nanospin.eu).

• Specific interest by academic and industrial partners in:

– the limit resolution for magnetic scanning probe microscopy and its thermal dependence for biosensors

– RF properties of nanoparticles for hyperthermia applications.

– For soft magnetic films and in spin valve multilayers, the determination of standard magnetic parameters (M_s, K_u, Gilbert damping) for different film thicknesses and interfaces is needed with high accuracy for the improvement of micromagnetic calculations used in device development (memories, heads etc).

– Single particle detection. Hall sensors, SQUID sensors.

– NanoSQUID readout amplifier commercially available

4.1 Knowledge transfer

Knowledge transfer has been accomplished through specific contacts with stakeholders and selected scientific partners, which have been involved in the scientific activities. A wider diffusion of the information has been obtained by the creation and regular update of the project website with public access and with the final public workshop jointly organized by several project coordinators.

4.2 Impact

At the moment the largest market associated to NanoSpin activities is connected to the production of anisotropic magnetoresistive and Hall sensors for a wide range of applications in the automotive, consumer electronics, communications, industrial, aerospace and defence markets. This is a rather mature technology where the impact of our project is small but not negligible, in fact a new application oriented project is being started in this area. Also novel magnetic memory applications such as MRAM, ST-RAM and are being considered for mass production by several companies. The method developed within the Consortium for accurate measurements of Hall sensors in ambient conditions and separation of measurement artifacts has been successfully transferred to stakeholders. Finally there is an increasingly widespread use of magnetic nanoparticles in the biomedical sector, where the project has been able to provide specific measurement and calibration techniques. These techniques are being currently used for smaller project with a startup and another smaller company in Italy and for a new proposal with a large number of stakeholders in the biomedical field.

4.3 RECENT Publications

1. Michaela Kuepferling, Claudio Serpico , Matthew Pufall , William H. Rippard , T. Mitchell Wallis, , Atif Imtiaz , Pavol Krivosik , Massimo Pasquale , Pavel Kabos Two modes behavior of vortex oscillations in spin-transfer nano-contacts subject to in-plane magnetic fields Applied Physics Letters 96: 25. 252507-3 June 2010

2. O. Kazakova, V. Panchal, J. Gallop, P. See, D. C. Cox, M. Spasova, and L. F. Cohen, ‘Ultra-small particle detection using a nano-sized Hall sensor’. J. Appl. Phys. 107, 09E708 (2010).

3. O. Kazakova, L. Hao, D. Cox, P. See, and J. Gallop, Magnetic nanoparticle detection using nano-SQUID sensors. Submitted to J. Phys. D.

4. L Hao et al Magnetic nanoparticle detection using nano-SQUID sensors J. Phys. D: Appl. Phys. 43 474004 2010

5. R. B. Morgunov, F. B. Mushenok and O. Kazakova, ‘Nonlinear spin-wave phenomena in [Mn{(R/S)-pn}₂]₂[Mn{(R/S)-pn}₂H₂O][Cr(CN)₆] molecular ferrimagnet’. Phys. Rev. B. 82, 134439 (2010).

6. O. Kazakova, L. Hao, D. Cox, P. See, and J. Gallop, ‘Magnetic nanoparticle detection using nano-SQUID sensors’. J. Phys. D. 43, 474004 (2010).

7. L. Di Michele, C. Shelly, J. Gallop, and O. Kazakova, 'Single particle detection: phase control in submicron Hall sensors’. J. of Appl. Phys. In press.

8. F. Ruede, S. Bechstein, L. Hao, C. Aßmann, Th. Schurig, J. Gallop, O. Kazakova, J. Beyer, and D. Drung, ‘Readout of NanoSQUID Sensors Using a SQUID Amplifier’. IEEE Transactions on Applied Superconductivity. In press.

9. N. Liebing, S. Serrano-Guisan, A. Caprile,3, E. S. Olivetti, F. Celegato, M. Pasquale, A. Muller and H.W. Schumacher Influence of sample geometry on inductive damping measurement methods IEEE Transactions on Magnetics 2011 in press

4.4 OTHER REleted PUBLICATIONS, presentations, conferences

Publications:

· M.Pasquale, E.S. Olivetti, M.Coïsson, P.Rizzi, G.Bertotti "Ferromagnetic resonance and superparamagnetic behavior of iron oxide nanoparticles injected in porous anodic alumina" J. of Appl. Phys. 103, 07D527 (2008)

· S. Serrano-Guisan et al., Phys. Rev. Lett., 101, 087201 (2008)

· S. Serrano-Guisan et al., J. Phys D.: Appl. Phys. 41, 164015 (2008).

· D. Drung, J. Beyer, M. Peters, Th. Schurig; Novel SQUID curren sensors with high linearity at high frequencies, Invited talk at the ASC'08, Chicago,

· D. Drung, J. Beyer, M. Peters, Th. Schurig; Novel SQUID curren sensors with high linearity at high frequencies, accepted for publication in IEEE Trans. Appl. Supercond.

· invited talk related to L. Hao, J.C. Macfarlane, J.C. Gallop, D. Cox, J. Beyer, D. Drung, and T. Schurig; Measurement and noise performance of nano-superconducting-quantum-interference devices fabricated by focused ion beam; Appl. Phys. Lett. 92, 192507 (2008).

· Kazakova, R. Morgunov, J. Kulkarni, J. Holmes, and L. Ottaviano. 'Effect of dimensionality on the spin dynamics of GeMn systems: Electron spin resonance measurements'. Phys. Rev. B, 77, 235317 (2008).

· R. Morgunov, M.Farle, M. Passacantando, L. Ottaviano, and O. Kazakova. 'Electron Spin Resonance and Microwave Magnetoresistance in Ge:Mn Thin Films' Phys. Rev. B 78, 045206 (2008).

· M. I. van der Meulen, N. Petkov, M. A. Morris, O. Kazakova, X. Han, K. L. Wang, A. P. Jacobs, and J. D. Holmes, 'Single Crystalline Ge1-xMnx Nanowires as Building Blocks for Nanoelectronics'. Nano Lett., 9, 50 (2009).

· R. B. Morgunov, A. I. Dmitriev, Y. Tanimoto, and O. Kazakova, 'Electron spin resonance of charge carriers and antiferromagnetic clusters in Ge0.99Cr0.01 nanowires', J. Appl. Phys. In press. 105 (2009).

· I. Dmitriev, R. B. Morgunov, O. Kazakova, and Y. Tanimoto, 'Spin-wave resonance in GeMn thin films possessing percolation ferromagnetic ordering' J. Exp. And Theoretical. Physics. Russian version. Accepted. June 2009.

· L. Hao, D. C. Cox and J C Gallop, 'Characteristics of focussed ion beam nano Josephson devices' Superconducting Science and technology. Accepted. 2009.

· Kazakova, M. I. van der Meulen, N. Petkov, and J. D Holmes, Magnetic Properties of Single-Crystalline Ge1-xMnx Nanowires. Submitted to IEEE Trans. on Magn. (2009).

· Kazakova, J. C. Gallop, P. See, D. Cox, G. K. Perkins, J. D. Moore, and L. F. Cohen Detection of a micron-sized magnetic particle using InSb Hall sensor Submitted to IEEE Trans. on Magn. (2009).

· L. FRICKE, S. SERRANO-GUISAN,H. W. SCHUMACHER: “Parmeter dependence of resonant spin torque magnetization reversal” IEEE Trans. Magn., submitted (2009).

· K.-F. Braun, S. Sievers, M. Albrecht, U. Siegner, K. Landfester, V. Holzapfel “Stability of the magnetic domain structure of nanoparticle thin films against external fields” Journal of Magnetism and Magnetic Materials 321 (2009), pp. 3719-3725.

· O. Kazakova, R. Morgunov, J. Kulkarni, J. Holmes, and L. Ottaviano. ‘Effect of dimensionality on the spin dynamics of GeMn systems: Electron spin resonance measurements’. Phys. Rev. B, 77, 235317 (2008).

· R. Morgunov, M.Farle, M. Passacantando, L. Ottaviano, and O. Kazakova. ‘Electron Spin Resonance and Microwave Magnetoresistance in Ge:Mn Thin Films’ Phys. Rev. B 78, 045206 (2008).

· M. I. van der Meulen, N. Petkov, M. A. Morris, O. Kazakova, X. Han, K. L. Wang, A. P. Jacobs, and J. D. Holmes, 'Single Crystalline Ge_1-xMn_x Nanowires as Building Blocks for Nanoelectronics'. Nano Lett., 9, 50 (2009).

· R. B. Morgunov, A. I. Dmitriev, Y. Tanimoto, and O. Kazakova, ‘Electron spin resonance of charge carriers and antiferromagnetic clusters in Ge_0.99Cr_0.01 nanowires’, J. Appl. Phys. 105, 093922 (2009).

· A. I. Dmitriev, R. B. Morgunov, O. Kazakova, and Y. Tanimoto, ‘Spin-wave resonance in GeMn thin films possessing percolation ferromagnetic ordering’, J. Exp. and Theor. Phys. 108, p. 985 (2009).

· R. B. Morgunov, A. I. Dmitriev and O. L. Kazakova, ‘Percolation ferromagnetism and spin waves in Ge:Mn thin films’. Phys. Rev. B 80, 085205 (2009).

· I. Rod et al., O. Kazakova, D. C. Cox, M. Spasova, and M. Farle. ‘Route to single magnetic particle detection: carbon nanotube decorated with a finite number of nanocubes’, Nanotechnology 20, 335301 (2009).

· O. Kazakova, M. I. van der Meulen, N. Petkov, and J. D Holmes,‘Magnetic Properties of Single-Crystalline Ge_1-xMn_x Nanowires’. IEEE Trans. on Magn. 45, 4085 (2009).

· O. Kazakova, R. Morgunov, A. Dmitriev, A. Chernenkaya, Y. Tanimoto, and L. Ottaviano, ‘Influence of Growth Temperature on the Percolation in Ge:Mn thin films’. Submitted to IEEE Trans. on Magn.

· O. Kazakova, J. C. Gallop, D. C. Cox, E. Brown, A. Cuenat, and K. Suzuki. ‘Optimization of 2DEG InAs/GaSb Hall Sensors for Single Particle Detection’. IEEE Tran. on Magn. 44, 4480 (2008).

· L. Hao, D. C. Cox and J C Gallop, ‘Characteristics of focussed ion beam nano Josephson devices’ Superconducting Science and technology. 22, 064011 (2009).

· O. Kazakova, J. C. Gallop, P. See, D. Cox, G. K. Perkins, J. D. Moore, and L. F. Cohen,Detection of a micron-sized magnetic particle using InSb Hall sensor. IEEE Trans. on Magn. 45, 4499 (2009).

· S. SERRANO-GUISAN, HAN-CHUN WU, C. BOOTHMAN, M. ABID, I. V. SHVETS,H. W. SCHUMACHER: “Time-resolved precessional magnetization dynamics in Fe₃O₄ thin films by pulsed inductive microwave magnetometry” Appl. Phys. Lett., submitted (2010).

· K.-F. Braun, S. Sievers, D. Eberbeck, S. Gustafsson, E. Olsson, H.W. Schumacher, U. Siegner, ‘Quantitative measurement of the magnetic moment of an individual magnetic nanoparticle by magnetic force microscopy', Submitted to Nanotechnology.

· K.-F. Braun, S. Sievers, M. Albrecht, U. Siegner, K. Landfester, V. Holzapfel, ‘Stability of the magnetic domain structure of nanoparticle thin films against external fields ', Journal of Magnetism and Magnetic Materials 321 (2009), pp. 3719-3725.

· Michaela Kuepferling, Claudio Serpico , Matthew Pufall , William H. Rippard , T. Mitchell Wallis, , Atif Imtiaz , Pavol Krivosik , Massimo Pasquale , Pavel Kabos Two modes behavior of vortex oscillations in spin-transfer nano-contacts subject to in-plane magnetic fields Applied Physics Letters 96: 25. 252507-3 June 2010

· O. Kazakova, V. Panchal, J. Gallop, P. See, D. C. Cox, M. Spasova, and L. F. Cohen, ‘Ultra-small particle detection using a nano-sized Hall sensor’. J. Appl. Phys. 107, 09E708 (2010).

· O. Kazakova, L. Hao, D. Cox, P. See, and J. Gallop, Magnetic nanoparticle detection using nano-SQUID sensors. Submitted to J. Phys. D.

· L Hao et al Magnetic nanoparticle detection using nano-SQUID sensors J. Phys. D: Appl. Phys. 43 474004 2010

· R. B. Morgunov, F. B. Mushenok and O. Kazakova, ‘Nonlinear spin-wave phenomena in [Mn{(R/S)-pn}₂]₂[Mn{(R/S)-pn}₂H₂O][Cr(CN)₆] molecular ferrimagnet’. Phys. Rev. B. 82, 134439 (2010).

· O. Kazakova, L. Hao, D. Cox, P. See, and J. Gallop, ‘Magnetic nanoparticle detection using nano-SQUID sensors’. J. Phys. D. 43, 474004 (2010).

· L. Di Michele, C. Shelly, J. Gallop, and O. Kazakova, 'Single particle detection: phase control in submicron Hall sensors’. J. of Appl. Phys. In press.

· F. Ruede, S. Bechstein, L. Hao, C. Aßmann, Th. Schurig, J. Gallop, O. Kazakova, J. Beyer, and D. Drung, ‘Readout of NanoSQUID Sensors Using a SQUID Amplifier’. IEEE Transactions on Applied Superconductivity. In press.

Conferences

· O. Kazakova, V. Panchal, J. Gallop, P. See, D. C. Cox, M. Spasova, and L. F. Cohen, ‘Ultra-small particle detection using a nano-sized Hall sensor’. Submitted to J. Appl. Phys.

· Magnetic Properties of Single-Crystalline Ge1-xMnx Nanowires O. Kazakova, M. I. van der Meulen, N. Petkov, and J. D Holmes INTERMAG 2009

· Detection of a micron-sized magnetic particle using InSb Hall sensor O. Kazakova, J. C. Gallop, P. See, D. Cox, G. K. Perkins, J. D. Moore, and L. F. Cohen INTERMAG 2009

· Doublet sub-GHz peaks in the spectra of magnetization oscillations in spin-transfer nanocontacts. M. Kuepferling1, C. Serpico2, M. R. Pufall3, M. T.Wallis3, R. Heindl3, H. Nembach3, W. H. Rippard3, A. Imtiaz3, M.Pasquale1, P. Kabos3 INTERMAG 2009

· Hard transitions to magnetic vortex self-oscillations in spin-transfer nanocontacts. M. T.Wallis, C. Serpico, M. Kuepferling, H. Nembach, M. R. Pufall, W. H. Rippard, A. Imtiaz, M. Pasquale, P. Krivosik, P. Kabos INTERMAG 2009

· Presentation at SMM Conference Torino Sept. 2009: Structural characteristics and magnetic properties of Fe oxide nanoparticles M. Pasquale, E. Olivetti, P. Rizzi, V. A. Coleman, J. Herrmann (NMI Lindfield NSW Australia)

· M. Pasquale Presentation at the National Conference on Magnetism Roma Oct. 2009 FUNCTIONALIZED MAGNETIC NANOPARTICLES FOR BIOLOGICAL APPLICATIONS

· A tutorial on "Integration of Magnetoelectronics with CMOS" has been arranged and an invited symposium on the same topic was organized within the 2009 Intermag Conference sponsored by the IEEE Magnetics Society (May 2009 Sacramento, Ca Conference Chairman M. Pasquale). www.intermagconference.com

· Presentation to Intermag Conference Sacramento CA: ER-07. Doublet sub-GHz peaks in the spectra of magnetization oscillations in spin-transfer nanocontacts. M. Kuepferling 1, C. Serpico2, M.R. Pufall3, M.T.Wallis3, R. Heindl3, H. Nembach3, W.H. Rippard3, A. Imtiaz3, M. Pasquale1 and P. Kabos3 1. INRiM Torino, Italy; 2. University of Naples Federico II, Napoli, Italy; 3. NIST, Boulder, CO, USA

· Presentation to Intermag Conference Sacramento CA: GD-10. Hard transitions to magnetic vortex selfoscillations in spin-transfer nanocontacts. M.T.Wallis 1,C. Serpico2, M. Kuepferling3, H. Nembach1, M.R. Pufall1, W.H. Rippard1, A. Imtiaz1, M. Pasquale3, P. Krivosik4 and P. Kabos1 1. NIST, Boulder, CO, USA; 2. Università di Napoli “Federico II”; 3. INRiM, Torino, Italy; 4. Colorado State University

· Presentation at SMM Conference Torino Sept. 2009: Analysis of field-induced asymmetric switching in nanopillar devices Paolo Bortolotti, Michaela Kuepferling, Massimo Pasquale

· Presentation at SMM Conference Torino Sept. 2009: Magnetization properties of FeTb thin films A. Magni, F. Celegato, M. Coisson, E.S. Olivetti, M. Pasquale, C.P. Sasso (to be published on IEEE Trans. Mag.)

· Presentation at SMM Conference Torino Sept. 2009: Ferromagnetic resonance and damping in soft magnetic films: measurements and intercomparison M. Pasquale, G. Bertotti, E. Olivetti, M. Coisson, F. Celegato, Y. Endo,Y. Mitsuzuka, M. Yamaguchi, S. Serrano-Guisan, H.W.Schumacher, P. Kabos

· “Quasi Ballistic Spin Torque Magnetization Reversal”

· S. SERRANO-GUISAN, K. ROTT, G. REISS, J. LANGER, B. OCKER, AND H. W. SCHUMACHER, Invited talk, SPIE Optics & Photonics Conference, August 2009, San Diego, USA.

· “Traceable measurement of the magnetization of magnetic nanoparticles by magnetic force microscopy” K.-F. Braun, S. Sievers, L. Trahms, H.W. Schumacher: Accepted for Joint MMM / Intermag Conference 2010, Washington, USA.

· “Tunnel barrier thickness dependence of the free layer magnetization dynamics in CoFeB/MgO/CoFeB based magnetic tunnelling junctions” S. Serrano-Guisan, W. Skowronski, J. Wrona, M. Czapkiewicz, t. Stobiecki, J. Langer, B. Ocker, G. Reiss, H.W. Schumacher: Accepted for Joint MMM / Intermag Conference 2010, Washington, USA.

· “Parameter dependence of the spin transfer torque in magnetic tunnel junctions measured by time resolved magneto transport” S. Serrano-Guisan, K. Rott, G. Reiss, J. Langer, B. Ocker, and H. W. Schumacher MMM Conference 2008, November 2008, Austin, USA.

· “Readout of Nano SQUIDs” Frank Ruede, Cornelia Aßmann, Jörn Beyer, Thomas Schurig, Olga Kazakova, Ling Hao, John Gallop, Poster presented at workshop Kryoelektronische Bauelemente 2009” held October 4-6 in Oberhof, Germany.

· “Improvement of the spin torque reversal by resonant microwave currents” LUKAS FRICKE, SANTIAGO SERRANO-GUISAN, HANS-WERNER SCHUMACHER, Poster, DPG Spring Meeting, March 2009, Dresden, Germany.

· O. Kazakova et al. Intermag (May 2009, Sacramento, CA). Oral. ‘Single-crystalline Ge_1-xMn_xnanowires for nanoelectronic applications’.

· O. Kazakova et al. (December 2009, Warwick, UK). Poster. ‘Percolation nature of magnetic ordering in Ge:Mn’.

· O. Kazakova et al. (January 2010, Washington, US). Oral. ‘Percolation ferromagnetism in Ge:Mn thin films’.

· O. Kazakova et al. Intermag (May 2009, Sacramento, CA). Oral. ‘Detection of a micron-sized magnetic particle using InSb Hall sensor’.

· M. Bratko, et al. UK SPM (June 2009, Teddington, UK). Poster. ‘A Route To Traceable Calibration of Magnetic Probes’. 2^nd prize.

· L. Hao et al. (December 2009, Warwick, UK). Oral. ‘NanoSQUIDs for FePt magnetic nanoparticle detection'.

· O. Kazakova et al. (December 2009, Warwick, UK). Oral. ‘Detection of a single FePt nanoparticle using small Hall sensor’.

· O. Kazakova et al. (January 2010, Washington, US). Oral. ‘Ultra-small particle detection using a nano-sized Hall sensor’.

· O.Kazakova Joint Intermag – MMM conference. Oral. January 2010. Washington, DC.

· O.Kazakova ICFPM. Invited. June 2010. Uppsala, Sweden.

· O.Kazakova ASC. Oral. August 2010. Washington, DC.

· S. Sievers, K.-F. Braun, D. Eberbeck, and H.W. Schumacher, ‘Quantitative analysis of the magnetic moments of individual magnetic nanoparticles by magnetic force microscopy’, Joint MMM-INTERMAG 2010

· “Optimum tunnel barrier thickness for spin torque memory devices” S. SERRANO-GUISAN, W. SKOWRONSKI, N. LIEBLING, J. WRONA, M. CZAPKIEWICZ, T. STOBIECKI, J. LANGER, B. OCKER, G. REISS, H.W. SCHUMACHER: Poster, DPG Spring Meeting, March 2010, Regensburg, Germany.

· “Traceable measurement of the magnetization of magnetic nanoparticles by magnetic force microscopy” K.-F. BRAUN, S. SIEVERS, L. TRAHMS, H.W. SCHUMACHER: Talk, Joint MMM / Intermag Conference 2010, Washington, USA.

· “Tunnel barrier thickness dependence of the free layer magnetization dynamics in CoFeB/MgO/CoFeB based magnetic tunnelling junctions” S. SERRANO-GUISAN, W. SKOWRONSKI, J. WRONA, M. CZAPKIEWICZ, T. STOBIECKI, J. LANGER, B. OCKER, G. REISS, H.W. SCHUMACHER: Talk, Joint MMM / Intermag Conference 2010, Washington, USA.

· Oral Presentation at CPEM 2010 “COMPARISON OF FERROMAGNETIC RESONANCE AND DAMPING IN PERMALLOY FILMS USING TIME AND FREQUENCY DOMAIN TECHNIQUES” M. Pasquale, G. Bertotti_,E.Olivetti, M. Coisson, F. Celegato, M. Kuepferling, INRiM, Torino, Italy Y.Endo,Y.Mitsuzuka, M. Yamaguchi Tohoku University, Sendai, Japan S. Serrano-Guisan, H.W. Schumacher Physikalisch-Technische Bundesanstalt PTB, Braunschweig, Germany P. Kabos NIST Boulder Co, USA

· M. Pasquale invited talk at the International Conference on Microwave Magnetics June 2010 Boston Wideband characterization of MnZn soft ferrites: DC to microwaves F. Fiorillo, M. Coïsson , C. Beatrice, M. Pasquale

· Tunnel barrier thickness dependence of the free layer magnetization dynamics in CoFeB/MgO/CoFeB based magnetic tunnelling junctions. S. Serrano-Guisan, W. Skowronski, J. Wrona, M. Czapkiewicz, t. Stobiecki, J. Langer, B. Ocker, G. Reiss, H.W. Schumacher. Contributed talk, Joint MMM / Intermag Conference 2010, Washington, USA

· Optimum tunnel barrier thickness for spin torque memory devices.S. Serrano-Guisan, W. Skowronski, N. Liebling, J. Wrona, M. Czapkiewicz, T. Stobiecki, J. Langer, B. Ocker, G. Reiss, H.W. Schumacher.Poster, DPG Spring Meeting, March 2010, Regensburg, Germany.

· Analysis of the magnetic moments of single magnetic nanoparticles with magnetic force microscopy. S. SIEVERS, T. DZIOMBA, K.-F. BRAUN, D. EBERBECK, H.W. SCHUMACHER, U. SIEGNER. Poster, Nanoscale 2010, October 2010, Brno, Czech Republic.

· Quantitative analysis of the magnetic moments of individual magnetic nanoparticles by magnetic force microscopy. S. SIEVERS, K. BRAUN, D. EBERBECK AND H.W. SCHUMACHER. Contributed talk, Joint MMM / Intermag Conference 2010, Washington, USA.

· Classification of super domains and super domain walls in permalloy antidot lattices. X. Hu, S. Sievers, A. Müller, V. Janke and H.W. Schumacher. Contributed talk, MMM 2010, Georgia, USA.

· O. Kazakova et al. ‘Magnetic particle detection using nano-Hall and nano-SQUID sensors’ Invited talk, ICFPM, Uppsala, Sweden, June 2010.

· O. Kazakova et al. ‘Methods of detection of small magnetic moments’ Tutorial. ISAF ICAPD. Edinburgh, August 2010.

· O. Kazakova et al. ‘Detection of a single biolabelled bead using a nano-sized Hall sensor’ Oral. NMAET IV, Teddington, UK, November 2010.

· O. Kazakova et al. ‘Single particle detection: phase control in submicron Hall sensors’ Oral, MMM, Atlanta, GA, November 2010.

· F. Ruede et al. ‘Readout of NanoSQUID Sensors Using a SQUID Amplifier’, poster presentation at ASC2010, Washington, August 9-13, 2010.

· F. Ruede et al. ‘Readout of NanoSQUID Sensors Using a SQUID Amplifier’, poster presentation at conference “Kryoelektronische Bauelemente 2010” Zeuthen, Oct. 3-5, 2010

· Classification of super domains and super domain walls in permalloy antidot lattices',

Xiukun Hu, Sibylle Sievers, Andre Müller, Volker Janke, Hans Werner Schumacher, 55th MMM 2011, Atlanta, November 2010

Presentations:

· O. Kazakova. (April 2009, at NTT, Tokyo, Japan). Invited seminar on magnetic nano-sensors.

· J. Gallop (May 2009, at PTB, Berlin (+videoconference transmitting to Braunschweig, Germany) ‘ SQUID metrology’.

· invited talks of Olga Kazakova NPL at MISM, ECOSS 25, Intel Forum and FNMA’09.

· In May 2009 John Gallop from NPL has visited PTB Berlin to discuss current joint activities. He gave a talk about SQUID metrology which was also transmitted in a video conference to PTB Braunschweig.

· Visit of H.W. Schumacher to Thales Group, Orsay (A. Fert) for talk on spin torque dynamics and discussion.

· Visit and talks of H. W. Schumacher at Singulus AG 12/2008 and Hitachi, Cambridge 2/2009

· A presentation of the NanoSpin activities was given at the EURAMET meeting on DC&Quantum Metrology held in Paris (M. Pasquale, June 2009, Paris)

· EURAMET meeting on DC&Quantum Metrology M. Pasquale KRISS Daejon June 2010

· Massimo Pasquale INRIM F. Piquemal Ralf Behr PTB Félicien Schopfer LNE Coordination meeting during CPEM Daejon for the final meeting in Berlin May 2011 of IMERA+ REUNIAM, JOSY:. ULQHE:. NANOSPIN:

· M. Pasquale CCEM Task Group on Electrical Measurements of Material Properties during CPEM Daejon.

· Journée Technique : Nanomatériaux, quels bénéfices pour quelles performances ?, mars 2010.Nicolas Feltin, « Nanométrologie : La métrologie au service des Nanosciences & Nanotechnologies », talk.

· 4th Summer School Nanosciences Ile-de-France, Domaine du Tremblay, 20-25 juin 2010

· F. Piquemal, « Quantum electrical metrology and nanotechnology” lecture

· 4th General Assembly EURAMET, Lisbon 27 May 2010, F. Piquemal (LNE) Scientific progress within iMERA+TP4“Electricity & Magnetism” Attendees : F. Piquemal (LNE), Nicolas Feltin (LNE)

· 22nd EURAMET Electricity Contact Persons Meeting, MIKES, 28-29 October 2010, F. Piquemal “Report on DC& Quantum Metrology subfield 2010”, 22nd EURAMET Electricity Contact Persons Meeting, MIKES, 28-29 October 2009, talk.

JRP Contract Number:	T4.J02
JRP Short Name:	NanoSpin
JRP Full Title:	Nanomagnetism and Spintronics
Period covered (dates):	From 01-June-2008	To	31-May-2011
JRP-Coordinator:
Name, title, organisation: Tel.: E-mail: JRP website address:	Massimo Pasquale, Dr. INRIM +390113919820 m.pasquale@inrim.it www.nanospin.eu
Other JRP partners:
Long name, (Short name), country:	PTB – Germany NPL – U.K. LNE – France UME – Turkey
REPORT STATUS: Public The research within this EURAMET joint research project has received funding from the European Union Seventh Framework Programme, ERA-NET Plus, under the iMERA-Plus Project – Grant Agreement No. 217257.

3.2.1 Inductive time and frequency domain metrology for fFMR and a of soft magnetic thin films

4.3 RECENT Publications

4.4 OTHER REleted PUBLICATIONS, presentations, conferences

· L Hao et al Magnetic nanoparticle detection using nano-SQUID sensors J. Phys. D: Appl. Phys. 43 474004 2010

3.2.1 Inductive time and frequency domain metrology for f_FMR and a of soft magnetic thin films