Rock salt structure GdO epitaxial thin film with a high ferromagnetic Curie temperature

Abstract

GdO with unusual valence of Gd2+ (4f75d1) has been known as the only gas phase so far. In this study, we report on the growth of solid phase rock salt structure GdO epitaxial thin films. The GdO thin film was an n-type semiconductor with the bandgap of 0.1 eV. The ferromagnetic Curie temperature (TC) was as high as 276 K, which was much higher than that of archetypal ferromagnetic rare earth monoxide EuO (TC = 69 K). TC increased slightly with electron doping similar to non-stoichiometric EuO1−δ, while decreased significantly with La doping probably caused by the magnetic dilution effect due to substitution of Gd with divalent La.