Molecular-beam epitaxy growth and magnetic properties of BeTe with Cr doping

Abstract

We report the growth and magnetic properties of BeTe with Cr doping grown on GaAs(001) substrate at Te-rich condition by solid-source molecular-beam epitaxy. Ferromagnetisms were observed for films with high Cr concentration, x. The Curie temperatures TC for x=0.13 and x=0.17 are 175±5 K, while the TC for x=0.27 is 250±5 K. Structural properties were studied by in situ reflection high-energy electron diffraction, atomic force microscopy, and x-ray diffraction. Be1-x Mnx Te and Cr1-δ Te films were also grown and compared with the Be(Cr)Te films. We show that the ferromagnetic ordering of Be(Cr)Te films can be attributed to precipitations of NiAs Cr1-δ Te. © 2006 American Institute of Physics.