The effect of pressure and disorder on half-metallicity of CoRuFeSi Quaternary Heusler alloy

Abstract

Heusler alloys possess some exceptional properties, such as high spin polarization and large Curie temperatures. These properties are quite sensitive to disorders. Therefore, it is quite important to investigate the effect of different disorders on electronic and magnetic properties of Heusler alloys. Keeping in view sensitivity of properties of Heusler alloys to disorder, effect of hydrostatic pressure, vacancies, swap and antisite disorder on electronic and magnetic properties of quaternary Heusler alloy CoRuFeSi is presented in this paper. Two concentrations of vacancy disorders, six type of swap disorders and twelve type of antisite disorders at four different concentrations have been studied. Under the effect of pressure, half-metallicity of CoRuFeSi is retained up to 30 GPa. A transition from perfect half-metallic to nearly half-metallic compound is observed above this pressure. In case of vacancy disorder, Co, Ru and Si vacancies are more probable to occur as compared to Fe vacancies. Among various swap disorders, Co-Ru, Co-Fe and Fe-Si swaps are most favourable due to low value of formation energies. Co-Ru and Fe-Si disordered structures shows 100% spin polarization at all concentrations which shows robustness of half-metallicity against these swap disorders. Among various antisite disorders, Co(Ru), Co(Si), Ru(Co), Ru(Si), Si(Co) and Si(Ru) have low values of formation energies and are most likely to occur. The value of energy gap decreased on introduction of various disorders which is due to emergence of new minority-spin states. These results would help in incorporating CoRuFeSi Heusler alloy in spintronic devices.