Theoretical study on anisotropic magnetoresistance effects of i == [100], I == [110], and I == [001] for ferromagnets with a crystal field of tetragonal symmetry

Satoshi Kokado, Masakiyo Tsunoda

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3 Citations (Scopus)

Abstract

Using the electron scattering theory, we obtain analytic expressions for anisotropic magnetoresistance (AMR) ratios for ferromagnets with a crystal field of tetragonal symmetry. Here, a tetragonal distortion exists in the [001] direction, the magnetization M lies in the (001) plane, and the current I flows in the [100], [010], or [001] direction. When the I direction is denoted by i, we obtain the AMR ratio as AMRiðiÞ ¼ Ci 0 þ Ci 2 cos 2i þ Ci 4 cos 4i . . . ¼ Ci j cos ji, with i = [100], [110], and [001], ϕ[100] = ϕ[001] = ϕ, and ϕ[110] = ϕA. The quantity ϕ (ϕA) is the P j¼0;2;4;... relative angle between M and the [100] ([110]) direction, and Ci j is a coefficient composed of a spin–orbit coupling constant, an exchange field, the crystal field, and resistivities. We elucidate the origin of Ci j cos ji and the features of Ci j. In addition, we obtain the relation C½ 4 100 ¼ C½ 4 110, which was experimentally observed for Ni, under a certain condition. We also qualitatively explain the experimental results of C½ 2 100, C½ 4 100, C½ 2 110, and C½ 4 110 at 293 K for Ni.

Original languageEnglish
Article number034706
Journaljournal of the physical society of japan
Volume88
Issue number3
DOIs
Publication statusPublished - 2019

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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