Magnetoelastic anisotropy in Heusler-type MnCoGa films

ホイスラー型MnCoGa薄膜における磁気弾性異方性

窪田 崇秀*; 高野 大地*; 小田 洋平*; Mohanty, S.*; 伊藤 啓太*; 松木 充弘*; 林田 誠弘*; Sun, M.*; 竹田 幸治   ; 斎藤 祐児  ; Bedanta, S.*; 木村 昭夫*; 高梨 弘毅*

Kubota, Takahide*; Takano, Daichi*; Kota, Yohei*; Mohanty, S.*; Ito, Keita*; Matsuki, Mitsuhiro*; Hayashida, Masahiro*; Sun, M.*; Takeda, Yukiharu; Saito, Yuji; Bedanta, S.*; Kimura, Akio*; Takanashi, Koki*

This study focuses on an inverse-type Heusler alloy, MnCoGa (MCG), with a small off-stoichiometry (), showing perpendicular magnetic anisotropy (PMA). We observed a relatively large uniaxial magnetocrystalline anisotropy constant () on the order of 10 J/m at room temperature in the MCG films with a small tetragonal distortion of a few percent. X-ray magnetic circular dichroism (XMCD) was employed to get insight into the origin for the PMA. Negligible angular variation of the orbital magnetic moment evaluated using the XMCD spectra suggested a minor role of the so-called Bruno's term to . The origin of the PMA was discussed based on the second-order perturbation theory in terms of the spin-orbit coupling, and first principles calculations, claiming that the mixing of the occupied - and the unoccupied -spin states is responsible for the PMA of the MCG films.