On the origin of room-temperature ferromagnetism in wide-gap semiconductors

The emerging field of semiconductor spintronics would be dramatically boosted if a semiconductor exhibiting room-temperature ferromagnetism could be found. Here, we discuss the recent stage of research, paying particular attention to the understanding of the observed room-temperature ferromagnetism in the wide-gap semiconductors GaMnN and ZnMnO. Since spinodal decomposition has been observed in these structures, we consider the possibilities of influencing density fluctuations of the alloys to obtain ferromagnetic semiconductors with required functionalities. We contrast these compounds with (In,Mn)As and (Ga,Mn)As, where the ferromagnetism is well understood, albeit well below room temperature.