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Reliable measurement of magnetic fields on the nanometer scale

Foundations for the reliable measurement of magnetic stray fields with spatial resolutions down to 10 nm

PTB-News 2.2020
29.04.2020
Especially interesting for

magnetic sensor technology

magnetic metrology

So far, no internationally standardized measurement procedures have been available to measure magnetic field distributions that vary spatially on the nanometer scale. The NanoMag EMPIR metrology research project, which was spearheaded by PTB and has recently been completed with success, bridges this gap and will allow internationally comparable measurements of magnetic field distributions with high spatial resolution.

Test sample with magnetic structures used for the measurements performed within the scope of the interlaboratory comparison. The light green areas consist of a magnetic layer; in the darker areas, this layer was removed by means of lithography.

To further develop magnetic system components such as sensors and magnetic memories, industry needs traceable magnetic field measuring systems with the best possible spatial resolution. Magnetic field measurement procedures can be traced to a quantum standard by means of nuclear resonance and are well established, but so far, measurement procedures with spatial resolution could only be used qualitatively or for relatively large structures.

The partners of the recently completed NanoMag project have therefore developed several procedures with high spatial resolutions, elaborated calibration procedures and made reference materials available for calibration.

One of the most relevant project results was that it had been the first time that measurement procedures for magnetic field distributions traceable to the SI with the highest possible spatial resolutions of down to 10 nm had been developed, tested and validated by an international interlaboratory comparison. Within the scope of this comparison – with the participation of PTB – measurement data of magnetic force microscopes were successfully compared with each other in the field range around 0.1% T.

For one thing, this has laid the foundations for a corresponding measurement infrastructure at the three European metrology institutes involved in the research project. For another, an IEC standard on the spatially resolved measurement of magnetic field distributions has been developed based on the results. This standard will allow reliable and internationally comparable quantitative nanomagnetic measurements.

Additional information:

https://www.ptb.de/empir/nanomag.html

Contact

Hans Werner Schumacher
Department 2.5
Semiconductor Physics and Magnetism
Phone: +49 531 592-2500
hans.w.schumacher(at)ptb.de