Theoretical Study on In-plane, Out-of-plane, and Transverse Anisotropic Magnetoresistance Effects for Ferromagnetic Films

We theoretically study the in-plane, out-of-plane, and transverse anisotropic magnetoresistance (AMR) effects for ferromagnetic films [1]. We here use the electron scattering theory with an extrinsic mechanism, in which the conduction electron is scattered into the conduction state and the localized d states by impurities [2,3]. In the case of Fe₄N [4,5], the in-plane and out-of-plane AMR effects exhibit the negative AMR ratio of the twofold symmetry, while the transverse AMR effect shows the positive AMR ratio of the fourfold symmetry. The calculation results agree qualitatively well with the respective experimental results [1,4,5]. In addition, the peak structures of the AMR ratios reflect probability densities of a current direction of single atomic d states.

References: [1] S. Kokado and M. Tsunoda, Jpn. J. Appl. Phys. 64, 063001 (2025). [2] S. Kokado, M. Tsunoda, K. Harigaya, and A. Sakuma, J. Phys. Soc. Jpn. 81, 024705 (2012). [3] S. Kokado and M. Tsunoda, J. Phys. Soc. Jpn. 91, 044701 (2022). [4] M. Tsunoda, H. Takahashi, S. Kokado, Y. Komasaki, A. Sakuma, and M. Takahashi, Appl. Phys. Express 3, 113003 (2010). [5] K. Kabara, M. Tsunoda, and S. Kokado, AIP Advances 6, 055818 (2016).