Abstract
Ferromagnet/semiconductor hybrid structures are attractive and promising as artificial materials for 'semiconductor spintronics', because they can possess magnetic and/or spin-related functions and they have excellent compatibility with semiconductor device structures. We review our studies on the molecular beam epitaxy (MBE) growth of ferromagnet (MnAs)/III–V semiconductor layered heterostructures and nanoscale granular structures, and their magnetic, magneto-transport and magneto-optical properties. We show that, by careful control of MBE growth and processing, some useful magnetic or spin-related functions can be realized at room temperature.