Etude de premier principe de propriétés physiques des matériaux demi-métalliques pour des applications en spintronique.

Abstract

In this work, we have studied the structural, elastic, electronic phase transitions and magnetic properties of FeCrScSi (FCSS) and FeCrScGe (FCSG) quaternary Heusler compounds under hydrostatic pressure in the range of 0–50 GPa. The spin polarized calculations were carried out using the pseudo-potential plane wave (PP-PW) method within the generalized gradient approximation (GGA-PBE). The obtained ground-state structural properties are in good agreement with existing theoretical reports. In addition, the negative values of cohesive and formation energies reveal that both materials are stable and can be synthesized. The calculated elastic properties display that the studied materials are ductile and mechanically stable. Disregarding pressure effects, electronic structure analysis shows ferrimagnetic properties for FCSS and FCSG compounds. Under pressure, an electronic phase transition from spin filter material (SFM) to spin gapless semiconductor type II (SGS-II) is predicted at pressure values of 46.37 GPa and 32.48 GPa for FCSS and FCSG materials, respectively. Above these critical pressures, the considered materials exhibit a half metallic (HM) behavior. Finally, the calculated total magnetic moment of FCSS and FCSG compounds was found to be of the applied pressure, with an integer value of 3 μB, obeying the Slater-Pauling rule.