title: Long-range magnetic interaction and frustration in double perovskites Sr₂NiIrO₆ and Sr₂ZnIrO₆.
abstract: One often counts the nearest neighbouring (NN) exchange interactions for understanding of a magnetic insulator. Here we present first-principles calculations for the newly synthesized double perovskites Sr2NiIrO6 and Sr2ZnIrO6, and we find that the 2NN Ir-Ir antiferromagnetic coupling is even stronger than the 1NN Ni-Ir ferromagnetic one. Thus, the leading antiferromagnetic interactions in the fcc Ir sublattice give rise to a magnetic frustration. Sr2NiIrO6 and Sr2ZnIrO6 hence appear very similarly as a distorted low-temperature antiferromagnet (probably, of type III). This work highlights the long-range magnetic interactions of the delocalized 5d electrons, and it also addresses why the spin-orbit coupling is ineffective here.
authors.affiliation: Laboratory for Computational Physical Sciences (MOE), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China.
authors.forename: Xuedong
authors.initials: X
authors.lastname: Ou
authors.affiliation: Laboratory for Computational Physical Sciences (MOE), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China.
authors.forename: Zhengwei
authors.initials: Z
authors.lastname: Li
authors.affiliation: Laboratory for Computational Physical Sciences (MOE), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China.
authors.forename: Fengren
authors.initials: F
authors.lastname: Fan
authors.affiliation: Laboratory for Computational Physical Sciences (MOE), State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200433, China.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Wang
authors.affiliation: Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Wu