Systematic changes of the electronic structure of the diluted ferromagnetic oxide Li-doped NiFeO with hole doping

希薄強磁性酸化物Li添加NiFeOにおけるホール添加に伴う電子構造の系統的変化

小林 正起*; Hwang, J. I.*; Song, G.*; 大木 康弘*; 滝沢 優*; 藤森 淳; 竹田 幸治   ; 藤森 伸一   ; 寺井 恒太*; 岡根 哲夫  ; 斎藤 祐児  ; 山上 浩志; Lin, Y.-H.*; Nan, C.-W.*

Kobayashi, Masaki*; Hwang, J. I.*; Song, G.*; Oki, Yasuhiro*; Takizawa, Masaru*; Fujimori, Atsushi; Takeda, Yukiharu; Fujimori, Shinichi; Terai, Kota*; Okane, Tetsuo; Saito, Yuji; Yamagami, Hiroshi; Lin, Y.-H.*; Nan, C.-W.*

The electronic structure of Li-doped NiFeO has been investigated using photoemission spectroscopy (PES) and X-ray absorption spectroscopy (XAS). The Ni core-level PES and XAS spectra were not changed by Li doping. In contrast, the Fe intensity increased with Li doping relative to the Fe intensity. However, the increase of Fe is only of the doped Li content, suggesting that most of the doped holes enter the O and/or the charge-transferred configuration Ni . The Fe partial density of states and the host valence-band emission near valence-band maximum increased with Li content, consistent with the increase of electrical conductivity. Based on these findings, percolation of bound magnetic polarons is proposed as an origin of the ferromagnetic behavior.