Abstract
GaMnAs diluted magnetic semiconductor (DMS) thin films with high Mn compositions were grown on (001) GaAs substrate by low-temperature molecular beam epitaxy (LT-MBE) after inserting an InAs wetting layer onto the GaAs buffer. The growth follows the Stranski-Krastanov mode, which brings about special magnetic characteristics of Ga 0.88 Mn 0.12 As. The insulating-DMS-like M(T) relation of the as-grown sample indicates the existence of a high proportion of interstitial Mn atoms. The magnetization is greatly improved after annealing, and the low Curie temperature is suggested to be due to the surface hole-localization effect. The investigation on the magnetic anisotropy shows an almost isotropic characteristic of the magnetic properties, which is ascribed to the S-K growth mode. © 2008 Elsevier B.V. All rights reserved.