Photoemission and X-ray absorption studies of valence states in (Ni,Zn,Fe,Ti)O thin films exhibiting photoinduced magnetization

光電子分光及びX線吸収分光による光誘起磁化を示す(Ni,Zn,Fe,Ti)O薄膜における価電子帯の研究

小林 正起*; 大木 康弘*; 滝沢 優*; Song, G. S.*; 藤森 淳; 竹田 幸治   ; 寺井 恒太*; 岡根 哲夫  ; 藤森 伸一   ; 斎藤 祐児  ; 山上 浩志; 関 宗俊*; 川合 知二*; 田畑 仁*

Kobayashi, Masaki*; Oki, Yasuhiro*; Takizawa, Masaru*; Song, G. S.*; Fujimori, Atsushi; Takeda, Yukiharu; Terai, Kota*; Okane, Tetsuo; Fujimori, Shinichi; Saito, Yuji; Yamagami, Hiroshi; Seki, Munetoshi*; Kawai, Tomoji*; Tabata, Hitoshi*

By means of photoemission and X-ray absorption spectroscopy, we have studied the electronic structure of (Ni,Zn,Fe,Ti)O thin films, which exhibits a cluster glass behavior with a spin-freezing temperature of K and photo-induced magnetization (PIM) below . The Ni and Zn ions were found to be in the divalent states. Most of the Fe and Ti ions in the thin films were trivalent (Fe) and tetravalent (Ti), respectively. While Ti doping did not affect the valence states of the Ni and Zn ions, a small amount of Fe ions increased with Ti concentration, consistent with the proposed charge-transfer mechanism of PIM.