Direct measurement of the magnetic anisotropy field in Mn-Ga and Mn-Co-Ga Heusler films

Fowley C, Ouardi S, Kubota T, Yildirim O, Neudert A, Lenz K, Sluka V, Lindner J, Law JM, Mizukami S, Fecher GH, Felser C, Deac AM (2015)

Publication Type: Journal article

Publication year: 2015

Journal

Journal of Physics D: Applied Physics IOP Publishing: Hybrid Open Access

Book Volume: 48

Article Number: 164006

Journal Issue: 16

DOI: 10.1088/0022-3727/48/16/164006

Abstract

The static and dynamic magnetic properties of tetragonally distorted Mn-Ga based alloys were investigated. Static properties are determined in magnetic fields up to 6.5 T using SQUID magnetometry. For the pure Mn1.6Ga film, the saturation magnetisation is 0.36 MA m^-1 and the coercivity is 0.29 T. Partial substitution of Mn by Co results in Mn2.6Co0.3Ga1.1. The saturation magnetisation of those films drops to 0.2 MA m^-1 and the coercivity is increased to 1 T. The time-resolved magneto-optical Kerr effect (TR-MOKE) is used to probe the high-frequency dynamics of Mn-Ga. The ferromagnetic resonance frequency extrapolated to zero-field is found to be 125 GHz with a Gilbert damping, α, of 0.019. The anisotropy field is determined from both SQUID and TR-MOKE to be 4.5 T, corresponding to an effective anisotropy density of 0.81 MJ m^-3. Given the large anisotropy field of the Mn2.6Co0.3Ga1.1 film, pulsed magnetic fields up to 60 T are used to determine the field strength required to saturate the film in the plane. For this, the extraordinary Hall effect was employed as a probe of the local magnetisation. By integrating the reconstructed in-plane magnetisation curve, the effective anisotropy energy density for Mn2.6Co0.3Ga1.1 is determined to be 1.23 MJ m^-3.

Involved external institutions

Helmholtz-Zentrum Dresden-Rossendorf (HZDR)

Germany (DE) Max-Planck-Institut für Chemische Physik fester Stoffe (MPI CPfS) / Max Planck Institute for Chemical Physics of Solids

Germany (DE) Tohoku University

Japan (JP)

How to cite

APA:

Fowley, C., Ouardi, S., Kubota, T., Yildirim, O., Neudert, A., Lenz, K.,... Deac, A.M. (2015). Direct measurement of the magnetic anisotropy field in Mn-Ga and Mn-Co-Ga Heusler films. Journal of Physics D: Applied Physics, 48(16). https://doi.org/10.1088/0022-3727/48/16/164006

MLA:

Fowley, Ciaran, et al. "Direct measurement of the magnetic anisotropy field in Mn-Ga and Mn-Co-Ga Heusler films." Journal of Physics D: Applied Physics 48.16 (2015).

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