These are based on traditional semiconductors, but are doped with transition metals instead of, or in addition to, electronically active elements.
In particular, ZnO-based DMS with properties such as transparency in visual region and piezoelectricity have generated huge interest among the scientific community as a strong candidate for the fabrication of spin transistors and spin-polarized light-emitting diodes,[3] while copper doped TiO2 in the anatase phase of this material has further been predicted to exhibit favorable dilute magnetism.
[4] Hideo Ohno and his group at the Tohoku University were the first to measure ferromagnetism in transition metal doped compound semiconductors such as indium arsenide[5] and gallium arsenide[6] doped with manganese (the latter is commonly referred to as GaMnAs).
The pioneering work of Dietl et al. showed that a modified Zener model for magnetism[7] well describes the carrier dependence, as well as anisotropic properties of GaMnAs.
If there is an insufficient hole concentration in the magnetic semiconductor, then the Curie temperature would be very low or would exhibit only paramagnetism.