First-Principles Investigation of the Electronic and Magnetic Properties of RhCo-Based Quaternary Heusler Alloys

In this contribution, we present an ab initio investigation of the electronic and magnetic properties of some RhCo-based quaternary Heusler alloys (QH). QH compounds can be generated from doping the X₂YZ full Heusler alloys; in this case, we start our study by tracking the electronic and magnetic properties variation of cobalt-doped Rh₂MnSn. Our results reveal that Co-substitution at Rh sites of Rh_2−xCo_xMnSn (x = 0 to 2) transforms it into half-metallic material when x ≥ 1. The calculated magnetic moment is 4.68µ_B for Rh₂MnSn (x = 0), this value will increase with Co doping to be an integer 5 µ_B when x ≥ 1 obeys the Slater Pauling behavior. The spin polarization at the Fermi level varied from 20.76 to 100%. The Curie temperature (Tc) and exchange interaction are largely dependent on the valence electron number (Nv); for this purpose, we also identify some other quaternary RhCoMnZ (Z = Al, Si, Ga, Ge, Sn, Sb) compounds with different Nv. The exchange parameters (j_ij) and Tc are calculated using the LMTO method. The Tc is calculated with the mean-field approximation (MFA), and the results indicate that all compounds investigated have Tc evidently higher than room temperature making them promising candidates for spintronics applications. The latter results are in better agreement with available experimental and theoretical data.