(In,Fe)Sb layers with a Fe content up to 13 at. % have been grown on (001) GaAs substrates using the pulsed laser deposition. Transmission electron microscopy shows that the layers are epitaxial and free of second-phase inclusions. The observation of hysteretic magnetoresistance curves at temperatures up to 300 K and the investigations of magnetic circular dichroism reveal that the Curie point lies above room temperature. The resonant character of magnetic circular dichroism confirms the intrinsic ferromagnetism in the (In,Fe)Sb matrix. We suggest that the ferromagnetism of the (In,Fe)Sb matrix is not carrier-mediated and is apparently determined by the mechanism of superexchange interaction between Fe atoms.

It is established that GaAs-based semiconductor heterostructures containing a single layer delta-doped with manganese, obtained by combining the methods of metalorganic chemical vapor deposition (MOCVD) in a hydride system and laser ablation of solid targets in a common technological cycle, possess ferromagnetic properties. The structures demonstrate nonlinear magnetic-field dependences of the Hall resistance with a hysteresis (at a coercivity of about 80 Oe) and show a negative magnetoresistance (up to 4% in a magnetic field of 3000 Oe) at temperatures below the Curie point (T _C ≈ 30 K).

The possibility of fabricating a ferromagnetic injector based on a near-equiatomic CoPt alloy with pronounced perpendicular magnetization anisotropy in the InGaAs/GaAs spin light-emitting diode is shown. The physical properties of experimental spin light-emitting diode prototypes are comprehensively studied. Circularly polarized electroluminescence of fabricated diodes is obtained in zero magnetic field due to the remanent magnetization of CoPt layers.

The Hall effect in InMnAs layers with MnAs inclusions of 20–50 nm in size is studied both theoretically and experimentally. We find that the anomalous Hall effect can be explained by the Lorentz force caused by the magnetic field of ferromagnetic inclusions and by an inhomogeneous distribution of the current density in the layer. The hysteretic dependence of the average magnetization of ferromagnetic inclusions on an external magnetic field results in a hysteretic dependence of $R_{\mathrm{H}}\left(H_{\mathrm{ext}}\right)$. Thus, we show the possibility of a hysteretic $R_{\mathrm{H}}\left(H_{\mathrm{ext}}\right)$ dependence (i.e., observation of the anomalous Hall effect) in thin conductive layers with ferromagnetic inclusions in the absence of carriers' spin polarization.

The effect of elastic stresses (compressive, tensile) on the magnetic properties of epitaxial GaMnAs layers prepared by laser deposition of solid-state targets in a gas atmosphere on different buffer sublayers (In _x Ga_{1 − x} As and In _x Ga_{1 − x} P) and substrates (GaAs, InP) has been investigated. It has been established from the investigations of magnetic-field dependences of the Hall resistance that all layers exhibit ferromagnetic properties with the Curie temperature ∼50 K. It has been shown that, in the case of tensile stresses in GaMnAs layers (In _x Ga_{1 − x} As and In _x Ga_{1 − x} P buffers and InP substrate), the anomalous Hall effect shape demonstrates a predominant orientation of the easy-magnetization axis in the growth direction, unlike the GaMnAs layers prepared on a GaAs substrate (with compressive stresses), which demonstrate the predominance of the component of the magnetization vector in the layer plane.