The effect of carrier doping on magnetism and electronic behavior in double perovskite LaZnIrO.

Tuning of spin-orbit coupling and electron correlation effects in iridates by introducing electron or hole carriers can produce interesting physical phenomena. In this work, we experimentally investigate the electron/hole doping effect on magnetism and electrical transport in the canted antiferromagnetic (AFM) double perovskite LaZnIrO, where hole/electron doping are realized in two serial LaZn Li IrO (0  ⩽  x  ⩽  0.35) and LaZnGa IrO (0  ⩽  y   ⩽  0.3) compounds, respectively. The x-ray photoelectron spectroscopy (XPS) reveals the existence of Ir and Ir oxide states in the Li and Ga doped LaZnIrO. The magnetic susceptibilities and electron spin resonance (ESR) results reveal different responses between the Ir(5d) and Ir (5d) ions in doped LaZnIrO, the Ir ions have Van-Vleck paramagnetic contribution contrast to the completely nonmagnetic Ir ions. Moreover, the Li doping cause more dramatic suppression of transition temperature (T ) and net ferromagnetic (FM) moments. All the Li/Ga doped samples remain Mott insulating state well fitted by the variable-range-hopping (VRH) transport mechanism. As a comparison, hole-doping is more effective to enhance the electrical conductivity than the case of electron, suggesting possible asymmetry of density of states nearby the Fermi level.