Ferromagnetic Semiconductor-Metal Transition in Europium Monoxide

Abstract

We present a microscopical model to describe the simultaneous parato- ferromagnetic and semiconductor-to-metal transition in electrondoped EuO. The physical properties of the model are systematically studied, whereas the main remark is on the interplay between magnetic order and the transport properties. The theory correctly describes detailed experimental features of the conductivity and of the magnetization, obtained for EuO1-x or Gd-doped Gd_xEu_1-x0. In particular the doping dependence of the Curie temperature is reproduced The existence of correlation-induced local moments on the impurity sites is essential for this description.