Enhanced magnetism and persistent insulating state in Mn doped Sr2IrO4

Abstract

Abstract The influences of Mn substitution at the Ir site of Sr2IrO4 are investigated via a comprehensive study of the variation of structural parameters, the transport and magnetic properties of the Sr2Ir1−x Mn x O4 samples. The incorporation of Mn leads to an increase of the in-plane Ir–O–Ir bond angle, while it is not sufficient to drive the Mott-insulating state to a metallic state. Interestingly, we find a coexistence of Ir4+–O2−–Ir4+ super-exchange interaction and Mn3+–O2−–Mn4+ double exchange interaction in x ⩾ 0.06 samples. The Mn3+–O2−–Mn4+ ferromagnetic domains are isolated by the Ir4+–O2−–Ir4+ antiferromagnetic areas, leading to a severely localized electronic and magnetic states. The electron hopping between the localized states dominates the conductivity of the Sr2Ir1−x Mn x O4 samples.