Semiconductor ferromagnetic structures

Ferromagnetic semiconductor structures such as superlattices or trilayers f orm a new class of magnetic systems composed entirely of semiconductor mate rials. The examples are Ga1-xMnxAs-AlGaAs with the ferromagnetic layer of G aMnAs semimagnetic (diluted magnetic) semiconductor or EuS-PbS with the fer romagnetic member (EuS) of the family of europium chalcogenides. We discuss the spectrum of perspective ferromagnetic semiconductor materials, the eff ect of size and stress on magnetic properties of ultrathin semiconductor fe rromagnetic layers, and the effect of interlayer exchange in all-semiconduc tor systems.