Advanced characterisation of high anisotropy materials
In recent times, there has been a resurge in investigation into Heusler alloys in order to exploit their high spin polarisation, low Gilbert damping and tuneable magnetic properties for next generation spintronic devices.
Such materials should be characterised in terms of both their static and dynamic properties. To investigate such high anisotropy materials, with coercivities on the order of Teslas and anisotropy fields of order several tens of Tesla, large magnetic fields are required. For applications, one would generally desire a low magnetisation and high anisotropy. As a result, indirect magnetometry techniques, such as extraordinary Hall effect and magneto optical Kerr effect can be more advantageous than standard magnetometry techniques (such as SQUID/VSM).
Within the context of the TRANSPIRE project, we are investigating high-field magnetotransport in other high-anisotropy alloys to investigate the interlayer exchange field strength as well as the intralayer magnetic anisotropy fields.
Figure 1: exemplary high-field anomalous Hall data from Mn-Co-Ga , the combination of in-plane and out-of-plane applied fields allos for the caculation of the magneic anisotropy field, shown as µ0Hk in the right panel.
- “Direct measurement of the magnetic anisotropy field in Mn–Ga and Mn–Co–Ga Heusler films”, C Fowley, S Ouardi, T Kubota, Y Oguz, A Neudert, K Lenz, V Sluka, J Lindner, JM Law, S Mizukami, GH Fecher, C Felser, AM Deac, Journal of Physics D : Applied Physics, 48, 164006 (2015).