NEW III-V-DILUTED MAGNETIC SEMICONDUCTORS

A new class of diluted magnetic semiconductor (DMS) based on a III-V semiconductor is reviewed. The new DMS, (In,Mn)As, was made possible by low temperature molecular beam epitaxial growth. Magnetic measurements and x-ray diffraction showed homogeneous incorporation of Mn in the films under certain growth conditions, and inclusion of a MnAs-like phase if the conditions are not optimized. The films can be made either p- or n-type by choosing the growth conditions and/or doping. Homogeneous n-type (In,Mn)As layers were paramagnetic and showed negative magnetoresistance. On the other hand, remanent magnetization was observed in p-type samples at low temperature and an anomalous Hall effect associated with it. The presence of such effects was most readily explained in terms of formation of bound magnetic polarons. A first result of anomalous Hall effect in a heterojunction is also presented.