Cr doping-induced ferromagnetism in the spin-glass CdMnTe studied by X-ray magnetic circular dichroism

スピングラスCdMnTeにおけるCrドープ誘起強磁性のX線磁気円二色性による研究

Verma, V.*; 坂本 祥哉*; 石川 弘一郎*; Singh, V. R.*; 石上 啓介*; 芝田 悟朗 ; 門野 利治*; 小出 常晴*; 黒田 真司*; 藤森 淳*

Verma, V.*; Sakamoto, Shoya*; Ishikawa, Koichiro*; Singh, V. R.*; Ishigami, Keisuke*; Shibata, Goro; Kadono, Toshiharu*; Koide, Tsuneharu*; Kuroda, Shinji*; Fujimori, Atsushi*

The prototypical diluted magnetic semiconductor CdMnTe is a spin glass () or an antiferromagnet () but becomes ferromagnetic upon doping with a small amount of Cr atoms. To investigate the origin of the ferromagnetism in CdMnCrTe, we have studied its element specific magnetic properties by X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD). Measured XAS and XMCD spectra indicate that both Cr and Mn atoms are divalent and that the magnetic moments of Cr and Mn are aligned parallel. By analyzing the element-specific magnetization curves, we conclude that Cr doping leads to the formation of ferromagnetic or superparamagnetic clusters consisting of several Cr ions surrounded by a much larger number of Mn ions.