Highly Resistive Epitaxial Mg-Doped Gdn Thin Films

We report the growth by molecular beam epitaxy of highly resistive GdN, using intentional doping with magnesium. Mg-doped GdN layers with resistivities of 10(3) Omega cm and carrier concentrations of 10(16) cm(-3) are obtained for films with Mg concentrations up to 5 x 10(19) atoms/cm(3). X-ray diffraction rocking curves indicate that Mg-doped GdN films have crystalline quality very similar to undoped GdN films, showing that the Mg doping did not affect the structural properties of the films. A decrease of the Curie temperature with decreasing the electron density is observed, supporting a recently suggested magnetic polaron scenario [F. Natali, B. J. Ruck, H. J. Trodahl, D. L. Binh, S. Vezian, B. Damilano, Y. Cordier, F. Semond, and C. Meyer, Phys. Rev. B 87, 035202 (2013)]. (C) 2015 AIP Publishing LLC.