Magneto-Optical Probing of the Magnetic State and Phase Composition of InFeAs Layers

The spectral, temperature, and magnetic field dependences of the magneto-optical transversal Kerr effect (TKE) have been studied along with the optical spectra of InFeAs layers formed by ion implantation with further pulsed laser melting at different laser pulse energies. A strong dependence of the magneto-optical and optical properties of InFeAs layers on the pulse energy has been revealed. The TKE spectra of the specimen formed at a minimum pulse energy (W = 0.1 J/cm²) indicate the presence of ferromagnetic (In, Fe)As nanoclusters with a Curie temperature of ≈180 K in the weakly doped semiconductive matrix and the absence of secondary magnetic phases. The TKE spectra of layers formed at W = 0.15–0.4 J/cm² are a superposition of the contributions from ferromagnetic (In,Fe)As nanoareas distributed in the volume and near-surface Fe inclusions. The predominance of the iron contribution in the spectra indicates the intensification of Fe diffusion towards the surface with an increase in the laser pulse energy. Anisotropy in the magneto-optical and optical spectra confirms anisotropic chemical phase separation in the layers.