Unveiling the robustness of half-metallicity under strain effects of CoVYZ (Z = Si, Ge, Sn) alloys

Abstract

Based on density functional theory computations, a systematic analysis has been conducted to elucidate the physical attributes of CoVYZ (Z = Si, Ge, Sn) alloys. To treat the exchange and correlation effects, generalized gradient approximation has been incorporated using WIEN2k package. The structural characteristics assure that CoVYZ alloys are comparatively stable in magnetic phase and electronic properties reveal that these alloys are half-metallic. The band character spectra of CoVYZ alloys signify that the Fermi level is predominantly influenced by the dt_2g bands of Co-atom. The calculated values of total magnetic moment found to be µ_total= 3.0 ${\mu }_B/f.u,$ pointing the Slater-Pauling rule, ($M_{\mathrm{SPR}}=N_v-24){\mu }_{B.}$ In CoVYZ (Z = Si, Sn) alloys, Co exhibits ferrimagnetic coupling under specific strains: +1% to + 5 % for CoVYSi and at + 1 % for CoVYSn. At negative strains, a shift from antiferromagnetism to ferrimagnetism occurs with respect to the V atom: at −5% for Si, −7% for Ge and −10 % for Sn. The effect of uniform strain specifically on the electronic and magnetic characteristics revealed that half-metallicity sustain upto expansion (+6%@ a_o) and upto contraction (−13 %@ a_o) distinctly. The CoVYSn alloy found most robust, rendering its suitability for spintronic applications under harsh environment.