Element and orbital-specific observation of two-step magnetic transition in NpNiGa; X-ray magnetic circular dichroism study

NpNiGaの二段磁気転移の元素・軌道選択的観測; X線磁気円二色性による研究

岡根 哲夫  ; 大河内 拓雄*; 稲見 俊哉; 竹田 幸治   ; 藤森 伸一   ; 河村 直己*; 鈴木 基寛*; 筒井 智嗣*; 山上 浩志; 藤森 淳; 田中 新*; 青木 大*; 本間 佳哉*; 塩川 佳伸*; 山本 悦嗣  ; 芳賀 芳範   ; 中村 彰夫; 大貫 惇睦*

Okane, Tetsuo; Okochi, Takuo*; Inami, Toshiya; Takeda, Yukiharu; Fujimori, Shinichi; Kawamura, Naomi*; Suzuki, Motohiro*; Tsutsui, Satoshi*; Yamagami, Hiroshi; Fujimori, Atsushi; Tanaka, Arata*; Aoki, Dai*; Homma, Yoshiya*; Shiokawa, Yoshinobu*; Yamamoto, Etsuji; Haga, Yoshinori; Nakamura, Akio; Onuki, Yoshichika*

X-ray magnetic circular dichroism (XMCD) experiments were performed at the Np and the Ga absorption edges of NpNiGa to investigate the temperature-dependent changes of magnetic properties of Np 5 and Ga 4 electron states. By the sum-rule analysis of the Np XMCD data, the orbital magnetic moment and the spin magnetic moment were estimated for the Np 5 and 5 electronic configurations, and their comparison with the previous magnetization and neutron scattering experiments suggests that the 5 configuration is more likely than the 5 configuration in NpNiGa. It was found that tends to increase from the high-temperature low-moment ordered state to the low-temperature high-moment ordered state.