Propriétés magnéto-optiques des couches ultraminces et des slabs à base de métaux de transition

Abstract

By means of the first principle calculation, we have investigated the structural, magnetic and magneto-optical properties of the ultrathin films of Ni and Fe growth by pseudomorphic epitaxy on semi-infinite crystals of Ir(001) and Au(001) respectively given by the formula Nin/Ir(001) and Fen/Ag(001) with (n=1, 2, 3…). We have adopted a relativistic approach using DFT theorem with local spin density approximation (LSDA). To calculate the electronic structure, we have used the Spin-Polarized Relativistic (SPR) Linear Muffin-Tin Orbitals (LMTO) with the Atomic Sphere Approximation (ASA) method. The crystalline structure was calculated by a relaxation process of the studied systems. A body centered tetragonal (bct) pseudomorphic crystalline structure with a tetragonality ratio c/a larger than unity was found. The magnetic calculations revealed that the inter-plane coupling is ferromagnetic with an enhanced magnetic moment. Using the Kubo-Greenwood linear response; the dispersion of the optical conductivity tensor as a function of the frequency of the incoming electromagnetic radiation is calculated from the energy band structure and the polar magneto-optical Kerr effect spectra are given over a photon energy range extended to 15eV. The microscopic origin of the most interesting features of Kerr rotations are interpreted by interband transitions.