Evolution of magnetism in Ru doped Na2IrO3

Abstract

We synthesized Ru doped single crystalline samples of the honeycomb iridate material Na2IrO3 and studied their magnetic properties using AC and DC magnetic susceptibility. The parent compound Na2IrO3 is a spin orbit driven Mott insulator with long range order below TN = 15 K. We find that even smallest substitution of Ru changes the antiferromagnetic long range order state to a spin glass like state indicating the fragile nature of magnetism in Na2IrO3. We track the freezing temperature Tg as a function of Ru concentration and the shift of Tg with frequency f of the ac modulation in AC susceptibility which is found to be very different from canonical spin-glasses like Cu-Mn.