Magnetism and electronic structure of La2ZnIrO6 and La2MgIrO6: Candidate J(eff)=1/2 Mott insulators

作者：Cao Guixin^*; Subedi Alaska; Calder S; Yan J Q; Yi Jieyu; Gai Zheng; Poudel Lekhanath; Singh David J; Lumsden Mark D; Christianson A D; Sales Brian C; Mandrus David

来源：Physical Review B, 2013, 87(15): 155136.

DOI：10.1103/PhysRevB.87.155136

We study experimentally and theoretically the electronic and magnetic properties of two insulating double perovskites that show similar atomic and electronic structure but different magnetic properties. In magnetization measurements, La2ZnIrO6 displays weak ferromagnetic behavior below 7.5 K, whereas La2MgIrO6 shows antiferromagnetic behavior below T-N = 12 K. Electronic structure calculations find that the weak ferromagnetic behavior observed in La2ZnIrO6 is in fact due to canted antiferromagnetism. The calculations also predict canted antiferromagnetic behavior in La2MgIrO6, but intriguingly, this was not observed. Neutron diffraction measurements confirm the essentially antiferromagnetic behavior of both systems but lack the sensitivity to resolve the small (0.22 mu(B)/Ir) ferromagnetic component in La2ZnIrO6. Overall, the results presented here indicate the crucial role of spin-orbit coupling (SOC) and the on-site Coulomb repulsion on the magnetic, transport, and thermodynamic properties of both compounds. The electronic structure calculations show that both compounds, like Sr2IrO4, are J(eff) = 1/2 Mott insulators. Our present findings suggest that La2ZnIrO6 and La2MgIrO6 provide a newplayground to study the interplay between SOC and on-site Coulomb repulsion in a 5d transition-metal oxide. DOI: 10.1103/PhysRevB.87.155136

• 出版日期2013-4-19