Influence of the Quantum Well Structure and Growth Temperature on a Five-Layer InGaMnAs Quantum Well with an InGaAs Buffer Layer.

The influence of quantum well structure and growth temperature on a synthesized multilayer system composed of a five-layer InMnGaAs quantum well with an InGaAs buffer layer grown on semi-insulating (100)-oriented substrates prepared by low temperature molecular beam epitaxy was studied. The magnetization measurements using a superconducting quantum interference device indicated the existence of ferromagnetism with a Curie temperature above room temperature in the five-layer InGaMnAs quantum well structure with an InGaAs buffer layer in a GaAs matrix. X-ray diffraction and secondary ion mass spectroscopy measurements confirmed the second phase formation of ferromagnetic GaMn clusters. The ferromagnetism that exists in the five-layer of the InMnGaAs quantum well with the InGaAs buffer layer results from a superposition of the ferromagnetism of the low temperature region from the substitutional Mn ions into Ga sites or interstitial Mn ions as well as the presence of manganese ions dopant clusters such as GaMn clusters.