Berlin 2015 – scientific programme
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MA: Fachverband Magnetismus
MA 20: POSTER Ib
MA 20.34: Poster
Tuesday, March 17, 2015, 09:30–13:00, Poster A
intuitive explanation of anisotropic magnetoresistance (AMR) effect and necessary condition for half-metallic ferromagnet “negative AMR” — •satoshi kokado1, yuta kitagawa1, takuya ito1, and masakiyo tsunoda2 — 1Graduate School of Engineering, Shizuoka University, Hamamatsu, Japan — 2Graduate School of Engineering, Tohoku University, Sendai, Japan
The anisotropic magnetoresistance (AMR) effect is a phenomenon in which the electrical resistivity depends on the relative angle between the magnetization direction and the electric current direction. The AMR ratio, which is the efficiency of the effect, is defined by (ρ//− ρ⊥)/ρ⊥. Here, ρ∥ (ρ⊥) represents a resistivity for the case of the electrical current parallel to the magnetization (a resistivity for the case of the current perpendicular to the magnetization). The AMR effect has been experimentally studied for various ferromagnets since about 150 years ago. The intuitive explanation about the AMR effect, however, has scarcely been reported. In this study, we first derive a general expression of the AMR ratio extending the conventional model to a more general one [1 - 3]. Using the general expression, we next give the intuitive explanation about the AMR effect [2]. In addition, we show that the negative AMR ratio is a necessary condition for half-metallic ferromagnets [1,2].
[1] S. Kokado et al., J. Phys. Soc. Jpn. 81 024705 (2012).
[2] S. Kokado et al., Adv. Mater. Res. 750-752 978 (2013).
[3] S. Kokado et al., Phys. Status Solidi C 11 1026 (2014).