Etude Théorique des propriétés structurales électroniques et magnétiques d’alliage Full Heusler à base de terres rares

Abstract

In material physics, the change of the spin orientation is a way of reversing the magnetization of a layer in a magnetic tunnel junction. The current required for this phenomenon depends on the materials and the control of these is a major issue in the industrial sector. Physical approaches favor the use of materials with high spin polarization. These materials are called Half-metals ferromagnetic. Due to the existence of a pseudo-spin gap in minority spin at Fermi level, these compounds have a strong spin polarization. Our study focuses on rare earth Heusler alloys of the Rh2YIn type (Y = Nd, Sm) to determine their structural, electronic and magnetic properties. In this work, we have used the full potential linear augmented plane wave (FP-LAPW) method, applied in the Wien2k code, by adopting the Local Density Approximation LDA and the generalized gradient approximation formulated by Wu-Cohen GGA-WC (2006). The code algorithm is based on the DFT method. Our results reveal a semi-metallic behavior for rare earth based Full-Heusler Rh2YIn (Y=Nd, Sm) alloys. Indeed, the structure of the state density illustrates a polarization for the up orientation (metal character) and a pseudo gap at the down orientation.