Lately the production of nanocrystalline magnetic materials starting with coarse grained materials (top-down approach) has received increasing interest.*
The advantage of the top-down approach compared to the bottom-up approach ( e.g. using melt spinning, stacking of sheets, annealing treatments and other processing steps) is that rare-earth elements and additional processing steps such as stacking of sheets are not necessary.*
In the article “On the magnetic nanostructure of a Co–Cu alloy processed by high-pressure torsion” Martin Stückler, Christian Teichert, Aleksandar Matković, Heinz Krenn, Lukas Weissitsch, Stefan Wurster, Reinhard Pippan, Andrea Bachmaier present a preparation route of Co–Cu alloys with soft magnetic properties by high-pressure torsion deformation. Nanocrystalline, supersaturated single-phase microstructures are obtained after deformation of Co–Cu alloys, which are prepared from an initial powder mixture with Co-contents above 70 wt.%.*
The authors used NANOSENSORS SSS-MFMRmagnetic AFM probes optimized for high resolution magnetic force imaging in the quantitative analysis of the magnetic microstructure by magnetic force microscopy to understand the measured magnetic properties and correlated this to the detected changes in coercivity.
The achieved results by Martin Stückler et al. show that the rising coercivity can be explained by a magnetic hardening effect occurring in context with spinodal decomposition.*
*Martin Stückler, Christian Teichert, Aleksandar Matković, Heinz Krenn, Lukas Weissitsch, Stefan Wurster, Reinhard Pippan, Andrea Bachmaier On the magnetic nanostructure of a Co–Cu alloy processed by high-pressure torsion Journal of Science: Advanced Materials and Devices, Volume 6, Issue 1, March 2021, Pages 33-41 DOI: https://doi.org/10.1016/j.jsamd.2020.09.013
Open Access The article “On the magnetic nanostructure of a Co–Cu alloy processed by high-pressure torsion” by Martin Stückler, Christian Teichert, Aleksandar Matković, Heinz Krenn, Lukas Weissitsch, Stefan Wurster, Reinhard Pippan, Andrea Bachmaier is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
These sensors can be used for nanomechanical sensing, material assessment, static/pulsed-field torque magnetometry, force sensing, and other applications.
The new sensor chips share the common MSS features, i.e., a membrane (or platform) supported with four beams on which piezoresistors are embedded at the fixed ends.
In the newly developed sensor chips however, the sensing beams are longer than in MSS chips meant for odour sensing applications (SD-MSS-1K2G) and form “bending” and “torsional” axes.
There are now three types of Membrane-type Surface-stress Sensor (MSS) dedicated for torque magnetometry available.
All three have in common that for two different functional axes, differently designed piezoresistors are embedded to effectively sense the torque generated by the sample. Considering a use at cryogenic temperatures, the resistance of the piezoresistor is designed relatively low and in the range of 0.3 – 1.2 kΩ. Each piezoresistor can be individually connected so that various measurement configurations can be arranged by the user.