Investigation of the physical properties of the equiatomic quaternary Heusler alloy CoYCrZ (Z = Si and Ge): a DFT study

In this manuscript, we investigate the physical properties such as the magnetic and the electronic properties of the Co-based equiatomic quaternary Heusler alloy CoYCrZ (Z = Si and Ge). These investigations have been performed by employing the Quantum Espresso code in the framework of density functional theory (DFT). The generalized gradient approximation (GGA) of Perdew–Burke–Ernzerhof (PBE) is used for all these calculations. The band structures, and density of states calculations, show that all these materials CoYCrZ (Z = Si and Ge) exhibit a half-metallic (HM) behavior only for the structure type II. Moreover, this structure type II is found to be the most stable configuration for all these alloys. On the other hand, it has been found that the Slater–Pauling is well described for the compound CoYCrGe, only for the configuration type II. In particular, the equiatomic quaternary Heusler alloys CoYCrSi and CoYCrGe are found to be half-metallic for the structure type II. This is due to the fact that they have 100% spin polarization SP. Also, the existence of complete SP in the studied alloys is the reason for which these materials are useful for spintronic device applications.