Spin order manipulations in ferromagnetic semiconductor heterostructures

The discovery of ferromagnetism in Mn-based zinc-blende diluted magnetic III-V semiconductors, such as (Ga,Mn)As, and in p-type II-VI materials, such as (Zn,Mn)Te:N, allows one to explore, previously not available, combinations of quantum structures and ferromagnetism in semiconductors. Experimental results for (III,Mn)V materials, where the Mn atoms introduce spins, holes, and compensation centers, are compared to the case of (II,Mn)VI compounds in which the Curie temperatures TC above 1 K have been observed for the uniformly and modulation-doped p-type heterostructures, and also in the case of n-type heterostructures but under rather exotic conditions. Experiments demonstrating the spin injection as well as the tunability of TC by light and electric field are described for heterostructures in the layout of light emitting diodes and field-effect transistors.