Half-metallic ferrimagnets behavior of a new quaternary Heusler alloy CrCoScZ (Z = Si, Ge, Sn)

The structure, magnetism, electronic properties and Curie temperature of LiMgPdSn-type quaternary Heusler alloys, CrCoScZ (Z=Si, Ge, Sn), are intensively studied using first-principles calculations through generalized gradient approximation (GGA) within the density functional theory (DFT). We find that the new alloys are potential half-metallic ferrimagnets with stable lowest-energy structures and half-metallic gaps of about 0.7 eV at the Fermi level (EF). All alloys have a magnetic moment of 4 μB per primitive cell, in good agreement with the Slater–Pauling rule for half-metallic ferrimagnets with inverse-Heusler structures. The half-metallicity or high spin polarization can be reserved in transition-metal atom Cr–Sc swap disordered structures. The ferromagnetic coupling among the neighbor transition metals, the anti-ferromagnetic coupling among the next neighbor transition metals and the RKKY magnetic interaction referring to main group element play significant roles in the magnetism of CrCoScZ. Based on the mean field approximation, the Curie temperature is found to be higher than room temperature. Thus, CrCoScZ has potential applications in spin-injection devices. Graphical abstract