Determination of structural, mechanical, thermal and magnetic properties of Cr based new quaternary Heusler alloys with GGA and GGA+U

Abstract Structural, mechanical, thermal and magnetic properties of Quaternary Heusler alloys (QHA) CrFeTiZ (Z = Al, Si, Ge, Ga) are determined by employing full potential - linearized augmented plane wave (FP-LAPW) method using density functional theory (DFT). Geometry optimization of all these QHAs is accomplished and Type 2 is found the most stable. Elastic parameters reveal the mechanical stability and ductile behavior of all considered alloys. The calculated Debye Temperature ( θ D ) assured that these alloys can be appropriate for high temperature devices due to high thermal conductivity ( κ ) and melting temperature (T melt ). All these compounds are half metallic (HM) in nature as the band gap (E g ) is present in one spin orientation. The values of E g for CrFeTiAl and CrFeTiGa are 0.68 eV and 0.86 eV respectively which are obtained by employing generalized gradient approximation (GGA) while Hubbard parameter (U) with GGA is used to calculate E g of CrFeTiGe and CrFeTiSi and the E g are 0.93 eV and 0.9 eV. The calculated magnetic moment (MM) of CrFeTiZ (Z = Al, Si, Ge, Ga) alloys agrees with Slater-Pauling rule (SPR). From the obtained results it is envisaged that these materials are suitable candidates for spintronic and high temperature devices.