Etude et caract erisation du comportement electronique et magn etique de Heusler quaternaire de composition CoMnCrSi

Abstract

Spintronics is a discipline that exploits both the charge and the spin of electrons in the same materials, in order to obtain a device allowing, at the same time, the transport and storage of information. Heusler materials, by their outstanding electronic and magnetic properties, are o ered for good candidates to accomplish this functionality. In the thesis an investigation, by the theory of the functional density, is proposed to characterize a quaternary Heusler material : the CoMnCrSi. A plane wave pseudo-potential method and an approximation of generalized gradient exchange and correlation e ects, all implemented in the CASTEP code, are used. Structural, electronic and magnetic properties of this material are calculated and analyzed. The hydrostatic pressure e ect on the different properties is also discussed for a pressure range from -28GPA to 50 GPa. CoMnCrSpresents a semi-metallic behavior, its total magnetic moment obeys the Slater-Pauling rule and it results mainly from the magnetic moment of the chromium atom. The CoMnCrSi also has a strong spin polarization which makes it a convincing material for spintronic technological and industrial applications.