Electrical transport properties of bulk tetragonal CuMnAs

Abstract

Temperature-dependent resistivity ρ(T ) and magnetoresistance are measured in bulk tetragonal phase of antiferromagnetic CuMnAs and the latter is found to be anisotropic both due to structure and magnetic order. We compare these findings to model calculations with chemical disorder and finite-temperature phenomena included. The finite-temperature ab initio calculations are based on the alloy analogy model implemented within the coherent potential approximation and the results are in fair agreement with experimental data. Regarding the anisotropic magnetoresistance (AMR) which reaches a modest magnitude of 0.12%, we phenomenologically employ the Stoner-Wohlfarth model to identify temperature-dependent magnetic anisotropy of our samples and conclude that the field-dependence of AMR is more similar to that of antiferromagnets than ferromagnets, suggesting that the origin of AMR is not related to isolated Mn magnetic moments.

Anisotropic magneto-thermal transport in Co$_2$MnGa thin films

“…Similar schemes are used also in the context of AMR in antiferromagnets. [3] Coordinate system is chosen as follows: z is the surface normal vector, which is in the The basic simplifying assumption is that magnetisation M is saturated (which is plausible given the very narrow hysteresis loop shown in Fig. 1(b) and that we are in a single-domain state.…”

“…Electron transport phenomena in magnetically ordered materials span a vast range both historically and from the point of view of complexity. While some of them which have been known for a long time, such as the anisotropic magnetoresistance (AMR) [1], remain a subject of roughly constant interest until today [2][3][4] others rose to prominence only recently. Such is the case of the anomalous Nernst effect [5] (ANE) for example, an outstanding member of the field of spin caloritronics [6].…”

“…We discuss the applicability of a simple Stoner-Wohlfarth-based model (as used recently in a different context, for example in Ref. [3]) to the AMTP data and compare the ratio of amplitudes of AMTP and AMR in various samples and at different temperatures. We report crystalline contributions to both AMR and AMTP and interestingly, some of these seem missing (or at least they are significantly weaker) in the latter effect.…”

Readout of a antiferromagnetic spintronics systems by strong exchange coupling of Mn2Au and Permalloy

“…Having established current induced writing, still the read-out of the Néel vector orientation in a potential device poses a major challenge. The magnitude of the anisotropic magnetoresistance effects (AMR) associated with the reorientation of N of metallic antiferromagnets amounts to only 0.1-1 % [13,[19][20][21][22]. The spin-Hall magnetoresistance, most often utilized for insulating AFMs, is even smaller [7][8][9].…”

Hysteretic effects and magnetotransport of electrically switched CuMnAs

“…In this material, electrical control of the antiferromagnetic moments was also detected by the anisotropic magnetoresistance (AMR) [6]. However, the AMR-related signals were rather small, with relative resistance changes limited to tenths of percent [6][7][8][9]. Apart from CuMnAs, the electrical control of magnetic moments was also demonstrated in Mn 2 Au [10][11][12] and other antiferromagnetic materials [13][14][15][16].…”