Berlin 2024 – scientific programme
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MA: Fachverband Magnetismus
MA 18: Magnetic Imaging and Sensors I
MA 18.7: Talk
Tuesday, March 19, 2024, 11:00–11:15, EB 301
Novel micro-coil designs for investigations of individual magnetic nanowires — •Aniruddha Sathyadharma Prasad1,2, Rachappa Ravishankar1,2, Volker Neu1, Bernd Büchner1,2, and Thomas Mühl1 — 1IFW Dresden — 2TU Dresden
Iron filled carbon nanotubes (FeCNTs) have been shown to be excellent magnetic sensors for use in magnetic force microscopy (MFM)[1]. The high aspect ratio and monopole like behaviour of FeCNTs allow for performing quantitative stray field measurements of various magnetic samples. Their magnetic switching fields are as high as 400 mT, which aids in the magnetic stability while performing MFM measurements.
In this work, we present novel micro-coil designs which can generate magnetic flux densities > 600 mT localised at the nanoscale. These coils can be utilized to investigate the switching behaviour of individual nanowires and can also be used to switch the direction of the magnetic moment in FeCNT-based MFM probes. Peak fields achieved by previous micro-coil designs were in the order of tens of mT, which is insufficient for switching the FeCNTs. We overcome the limitations of the conventional micro-coil design by integrating several heat-sink structures to carry heat away from the centre of the coil. This allows for higher currents to be pushed into the coil, while keeping the local temperature below the melting point of the materials involved.
The inhomogeneous field distributions generated by the micro-coils additionally presents an opportunity to study the behaviour of magnetic nanowires in non-uniform magnetic fields.
[1] Freitag, N.H. et al. Commun Phys 6, 11 (2023).
Keywords: MFM; micro-coil; Nanowires; magnetic switching