Dresden 2017 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 22: Poster session I

MM 22.42: Poster

Montag, 20. März 2017, 19:00–20:00, P4

Relational expression between spin polarization ratio and anisotropic magnetoresistance ratio for nearly half-metallic ferromagnets — •Satoshi Kokado¹, Yuya Sakuraba², and Masakiyo Tsunoda³ — ¹Shizuoka University, Hamamatsu, Japan — ²National Institute for Materials Science, Tsukuba, Japan — ³Tohoku University, Sendai, Japan

A current-perpendicular-to-plane giant magnetoresistance effect for ferromagnet/metal/ferromagnet junctions increases with increasing the spin polarization ratio of resistivity, P_ρ, in the ferromagnet. A simple method to estimate P_ρ, however, has scarcely been proposed. In this study, we derive a simple relational expression between P_ρ and the anisotropic magnetoresistance ratio Δ ρ/ρ, and that between the spin polarization ratio of the density of states at the Fermi energy, P_DOS, and Δ ρ/ρ for nearly half-metallic ferromagnets [1]. We here use the two-current model for a system consisting of a spin-polarized conduction state and localized d states with spin–orbit interaction [1-3]. We find that P_ρ and P_DOS increase with increasing Δ ρ/ρ from 0 to a maximum value. In addition, we investigate P_ρ and P_DOS for a Co₂FeGa_0.5Ge_0.5 Heusler alloy [4] by substituting its experimentally observed Δ ρ/ρ into the respective expressions.

[1] S. Kokado et al., Jpn. J. Appl. Phys. 55, 108004 (2016).
[2] S. Kokado et al., J. Phys. Soc. Jpn. 81, 024705 (2012).
[3] S. Kokado et al., Adv. Mater. Res. 750-752, 978 (2013).
[4] Y. Sakuraba et al., Appl. Phys. Lett. 104, 172407 (2014).