Influence of the substrate temperature on the Curie temperature and charge carrier density of epitaxial Gd-doped EuO films

Abstract

Rare earth doping is a standard, yet experimentally poorly understood method to increase the Curie temperature (TC) of the ferromagnetic semiconductor EuO. Here, we report on the charge carrier density (n) and the TC of commonly used 4.2 at. % Gd-doped EuO films grown by molecular-beam epitaxy on (110) oriented YAlO3 substrates at various substrate temperatures (Tsub). Increasing Tsub leads to a decrease in n and TC. For high substrate temperatures the Gd-doping is rendered completely inactive: n and TC drop to the values of undoped EuO.