Orbital magnetic moment and coercivity of SiO-coated FePt nanoparticles studied by X-ray magnetic circular dichroism

X線吸収磁気円二色性測定によるSiOをコートしたFePtナノ粒子の軌道磁気モーメントと保磁力の研究

高橋 文雄*; 門野 利治*; 山本 真平*; Singh, V. R.*; Verma, V.*; 石上 啓介*; 芝田 悟朗*; 原野 貴幸*; 竹田 幸治   ; 岡根 哲夫  ; 斎藤 祐児  ; 山上 浩志; 高野 幹夫*; 藤森 淳

Takahashi, Yukio*; Kadono, Toshiharu*; Yamamoto, Shimpei*; Singh, V. R.*; Verma, V.*; Ishigami, Keisuke*; Shibata, Goro*; Harano, Takayuki*; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Yamagami, Hiroshi; Takano, Mikio*; Fujimori, Atsushi

We have investigated the spin and orbital magnetic moments of Fe in FePt nanoparticles in the -ordered phase coated with SiO by X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) measurements at the Fe absorption edges. The magnetic coercivity (H) was found to be as large as 1.8 T at room temperature, 3 times larger than the thin film value and 50 times larger than that of the gas phase condensed nanoparticles. The hysteresis curve is well explained by the Stoner-Wohlfarth model for noninteracting single-domain nanoparticles with the H distributed from 1 to 5 T.