Spin and current transport in the robust half-metallic magnet c-CoFeGe

Abstract

Abstract Spintronics is an emerging form of electronics based on the electrons’ spin degree of freedom for which materials with robust half-metallic ferromagnet character are very attractive. Here we determine the structural stability, electronic, magnetic, and mechanical properties of the half-Heusler (hH) compound CoFeGe, in particular also in its cubic form. The first-principles calculations suggest that the electronic structure is robust with 100% spin polarization at the Fermi level under hydrostatic pressure and uni-axial strain. Both the longitudinal and Hall current polarization are calculated and the longitudinal current polarization ( P L ) is found to be > 99 % and extremely robust under uniform pressure and uni-axial strain. The anomalous Hall conductivity and spin Hall conductivity of hH cubic CoFeGe (c-CoFeGe) are found to be ∼ − 100 S cm−1 and ∼ 39   ℏ / e S cm−1, respectively. Moreover, the Curie temperature of the alloy is calculated to be ∼524 K with a 3 μ B magnetic moment. Lastly, the calculated mechanical properties indicate that c-CoFeGe is ductile and mechanically stable with a bulk modulus of ≈154 GPa. Overall, this analysis reveals that cubic CoFeGe is a robust half-metallic ferromagnet and an interesting material for spintronic applications.