Growth process and characterization of magnetic semiconductors based on GeMn alloy films

The growth mechanism of thin Ge1−xMnx/Ge(100) diluted magnetic semiconductor films have been studied by reflection high energy electron diffraction (RHEED) technique and correlated to the structural and magnetic properties of the films provided by X‐ray diffraction (XRD) and magneto‐optical Kerr effect (MOKE), respectively. The RHEED analysis evidenced a transition from a bi‐dimensional to a three‐dimensional growth mechanism at deposition temperature, TG, lower than 433 K while XRD characterization showed a polycrystalline structure with Ge grain size depending on TG. At low TG (343 K) all the Ge1−xMnx films behaved superparamagnetically, while at TG = 433 K hysteresis loops were observed, with a maximum Curie temperature of ≈250 K, for 0.027 < x < 0.044. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)