The spin-dependent interactions in diluted magnetic semiconductors are reviewed. The non-trivial dependence of the p-d and the d-d exchange interactions, which rule the magnetic properties of these materials, on the electronic configuration of the magnetic ions is presented. Depending on the occupation numbers in the ionic d shell and the position of the d level with respect to the bands, both the kinetic exchange and the superexchange can lead to antiferromagnetic, ferromagnetic Kondo-like interactions or even orbital dependent, sensitive to Jahn-Teller distortion couplings. Finally, the interactions explaining the ferromagnetism in III-V and p-II-VI with Mn ions, the magnetic properties in semiconductor quantum wells and the interlayer spin correlations in magnetic/non-magnetic semiconductor superlattices are discussed.

https://iopscience.iop.org/article/10.1088/0268-1242/16/4/201/pdf

Spin interactions in diluted magnetic semiconductors and magnetic semiconductor structures

Neutron scattering studies of nanomagnetism and artificially structured materials

The interlayer coupling between (Ga,Mn)As ferromagnetic layers in all-semiconductor superlattices is studied theoretically within a tight-binding model, which takes into account the crystal, band and magnetic structure of the constituent superlattice components. It is shown that the mechanism originally introduced to describe the spin correlations in antiferromagnetic $\mathrm{Eu}\mathrm{Te}∕\mathrm{Pb}\mathrm{Te}$ superlattices, explains the experimental results observed in ferromagnetic semiconductor structures, i.e., both the antiferromagnetic coupling between ferromagnetic layers in IV-VI ($\mathrm{Eu}\mathrm{S}∕\mathrm{Pb}\mathrm{S}$ and $\mathrm{Eu}\mathrm{S}∕\mathrm{Yb}\mathrm{Se}$) superlattices as well as the ferromagnetic interlayer coupling in III-V $[(\mathrm{Ga},\mathrm{Mn})\mathrm{As}∕\mathrm{Ga}\mathrm{As}]$ multilayer structures. The model also allows prediction of (Ga,Mn)As-based structures, in which an antiferromagnetic interlayer coupling could be expected.

Interlayer exchange coupling in (Ga,Mn)As-based superlattices

Publisher Summary This chapter discusses low-dimensional structures of II–VI diluted magnetic semiconductors (DMS) with manganese and describes the carrier concentration induced ferromagnetism in Mn-based IV–VI DMS with a particular emphasis on Mn content and conducting hole concentration dependent paramagnetic–ferromagnetic–spin glass transitions in bulk crystals and thin layers of SnMnTe and related materials. The chapter also discusses the transport, magnetic, and optical properties of bulk crystals and thick epitaxial layers; low-dimensional quantum structures of IV–VI DMS with Eu; the magnetic and electrical properties of IV–VI semiconductors with Gd; and the magnetic and optical properties of all semiconductor ferromagnetic multilayers built of ferromagnetic EuS and nonmagnetic IV–VI (PbSe and PbS) semiconductors. The chapter describes DMS containing transition metals other than manganese. These materials never attracted as much attention as the ones containing Mn, mainly because of severe difficulties in their preparation, particularly when large percentages of the magnetic components were involved.

V. Nunez

Papers

Interlayer coupling in (111) {EuTe}/{PbTe} AFM multilayers

Interlayer spin coherence in antiferromagnetic EuTe/PbTe superlattices observed by polarized neutron diffraction