High Spin Polarization and Thermoelectric Efficiency of Half-Metallic Ferromagnetic CrYSn (Y = Ca, Sr) of Half-Heusler Compounds

In the present work we have performed self-consistent ab-initio calculation using the full-potential linearized augmented plane-wave method (FP-LAPW), based on the density functional theory (DFT) as implemented in the Wien2k code to study the structural, electronic, magnetic, thermodynamic and thermoelectric properties of the half-heusler compound CrYSn (Y = Ca, Sr) using generalized gradient approximation (GGA) described by Perdew-Burke-Ernzerhof (PBE), GGA+U and the modified Beck-Johnson correction (mBJ), the obtained results show that the compound is stable in the ferromagnetic state (FM) in a phase on one hand and has a half-metallic character (metallic nature in spin up channel and semiconductor one in spin down channel with an indirect gap) on the other hand thus, the compound is a good candidate for spintronic applications, moreover it shows a very interesting thermoelectric predisposition in the minority spin or spin down channel at room temperature consisting of a very high Seebeck coefficient, high electrical conductivity and figure of merit near unity for the two compounds. The thermodynamic properties of CrCaSn and CrSrSn compounds using Gibbs code are studied for the first time. This study showed that these compounds can be used in extreme thermodynamic conditions. Since no experimental data were reported until now concerning this compound, our theoretical predictions of electronic, thermodynamic and thermoelectric properties are likely to be experimentally verified.