Magnetotransport and magnetic properties of (Ga,Mn) as and its heterostructures

Introduction of high density of Mn in GaAs by low temperature molecular beam epitaxy results in a homogeneous diluted magnetic semiconductor (Ga,Mn) As, which exhibits ferromagnetism at low temperatures. Temperature and magnetic field dependence of magnetotransport and magnetization of (Ga,Mn) As films revealed the Curie temperature T_C which can be as high as 110 K and the p-d exchange, which explains T_C in the framework of the RKKY interaction. Multilayer heterostructures such as all-semiconductor ferromagnet/nonmagnet/ferromagnet trilayer structures and resonant tunneling diodes have been fabricated and studied. These heterostructure results show the potential of the present material system for exploring new physics and for developing new functionality toward future electronic and optical devices.