First principles calculations of 3d-4d transition metal based LiMgPdSn–type FeCrRuZ (Z = Al, Ga, In, Si) equiatomic quaternary Heusler alloys

Abstract

We have investigated the structural, electronic and magnetic properties of the equiatomic quaternary Heusler (EQH) alloys FeCrRuZ (Z = Al, Ga, In, Si) using density functional theory. The structural study reveals that all the FeCrRuZ (Z = Al, Ga, In, Si) alloys stabilized to Y1 type structural configuration with ferrimagnetic ordering. The spin-polarized density of states (DOS) calculation demonstrates that FeCrRuAl alloy exhibits unusual spin-gapless half-metallic (SG-HM) behavior with majority spin-up channel possessing metallic characteristic and minority spin-down channel showing spin-gapless nature. The FeCrRuSi, FeCrRuGa and FeCrRuIn alloys display half-metallic, nearly half-metallic and metallic nature, respectively. The FeCrRuAl and FeCrRuSi alloys greatly follow the Slater-Pauling rule and give 100% spin-polarization at the Fermi level with total integer magnetic moment of 1 and 2 μB, respectively. In all, the total magnetic moment of FeCrRuZ (Z = Al, Ga, In, Si) alloys is contributed mainly by Cr atoms. The origin of the half-metallic band gap is elucidated through a schematic molecular orbital (MO) diagram. Further, the role of main group elements on structural, electronic, magnetic and half-metallic properties are explored in greater detail.