Etude ab-initio des propriétés structurales, magnéto-électroniques des alliages d’Heusler quaternaires

Abstract

In this work, the structural, electronic and magnetic properties of some quaternary Heusler alloys (QH) based on RhCo were calculated using an ab-initio method. These compounds can be generated from doping of the ternary Heusler compounds; in this case, we begin our study by following the variation of structural, electronic and magnetic properties of Cobalt-doped of Rh2MnSn. The Co-substitution at Rh sites of Rh2-xCoxMnSn (x = 0 to 2) transforms it to half metallic material from the concentrations more than x=0,75. The magnetic properties reveal that the Co-doping increases the total magnetic moment; it is equal to 4.68 μB for Rh2MnSn to reach 5 μB in the range of half-metallic compounds founds. This integer value is obeying the Slater Pauling behavior with a 100% spin polarization. The exchange interaction parameters ( jij) and the Curie temperatures (Tc) of RhCoMnZ (Z = Al, Si, Ga, Ge, Sn, Sb) are also estimated, using the LMTO method implemented in the Questaal package. The Tc is calculated with mean field approximation (MFA), it is higher than ambient temperature for all compounds studied making them promising candidates for spintronic devices.