title: Significant enhancement of ferromagnetism in Zn1-xCrxTe doped with iodine as an n-type dopant.
abstract: The effect of additional doping of charge impurities was investigated in a ferromagnetic semiconductor Zn1-xCrxTe. It was found that the doping of iodine, which is expected to act as an n-type dopant in ZnTe, brought about a drastic enhancement of the ferromagnetism in Zn1-xCrxTe, while the grown films remained electrically insulating. In particular, at a fixed Cr composition of x=0.05, the ferromagnetic transition temperature TC increased up to 300 K at maximum due to the iodine doping from TC=30 K of the undoped counterpart, while the ferromagnetism disappeared due to the doping of nitrogen as a p-type dopant. The observed systematic correlation of ferromagnetism with the doping of charge impurities of both the p and n type, suggesting a key role of the position of Fermi level within the impurity d state, is discussed on the basis of the double-exchange interaction as a mechanism of ferromagnetism in this material.
authors.affiliation: Institute of Materials Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573, Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Ozaki
authors.forename: Nozomi
authors.initials: N
authors.lastname: Nishizawa
authors.forename: Stéphane
authors.initials: S
authors.lastname: Marcet
authors.forename: Shinji
authors.initials: S
authors.lastname: Kuroda
authors.forename: Osamu
authors.initials: O
authors.lastname: Eryu
authors.forename: Kôki
authors.initials: K
authors.lastname: Takita