MBE growth, structure and magnetic properties of MnAs on GaAs on a microscopic scale

Ferromagnetic MnAs layers with abrupt interfaces were grown by MBE on (001) and (311)A oriented GaAs substrates. At low growth rates and As-rich condi tions, the films are ((1) over bar 1 0 0) oriented on both templates. For M nAs/GaAs(0 0 1) layers it is demonstrated that realizing a well-ordered rec onstructed growth surface and the layer-by-layer growth mode on a thin MnAs buffer, films of high structural quality and very promising magnetic prope rties are obtained. The quality of thick films is limited by processes acco mpanying the beta --> alpha MnAs phase transition during sample cooling. Th e magnetic domains, their increase in size with increasing external magneti c field and their relation to topographical defects was studied by magnetic force microscopy combined with atomic force microscopy. (C) 2001 Elsevier Science B.V. All rights reserved.