Applied Physics Letters · 1996 · 242 citations · 0 references
Natural SciencesMaterials EngineeringMaterials ScienceMagnetic MaterialsNanotechnologySemiconductor MaterialsEpitaxial GrowthFerromagnetic MaterialsFerromagnetismMagnetic NanomaterialsSemiconductor HeterostructuresSemiconductor NanomaterialsAnnealingHeterostructuresMagnetic HeterostructuresMagnetic PropertiesMagnetic SemiconductorsMolecular Beam EpitaxyNanostructured FerromagnetsQuantum Well Growth
Spherical MnAs ferromagnetic particles with controllable diameters (5–30 nm) are embedded in a high quality GaAs matrix. The particles are formed in a two step process consisting of the epitaxy of a homogeneous Ga1−xMnxAs layer at low temperatures using molecular beam epitaxy followed by phase separation upon annealing. During the annealing step, the excess arsenic in the as-grown film forms magnetic MnAs precipitates with the Mn from the Ga1−xMnxAs lattice. Structural and room-temperature magnetic properties of the heterogeneous GaAs:MnAs films are described. The magnetic MnAs rich layers can be incorporated into semiconductor heterostructures as demonstrated by growing (GaAs/AlAs) multiple quantum well structures in combination with GaAs:MnAs layers.