Long-range magnetic interaction and frustration in double perovskite Sr${}_2$NiIrO${}_6$

Abstract

Sr${}_2$NiIrO${}_6$ would be a ferromagnetic (FM) insulator in terms of the common superexchange mechanism between the first nearest neighboring (1NN) magnetic ions Ni${}^{2+}$ ($t_{2g}^6{e}_g^2$) and Ir${}^{6+}$ ($t_{2g}^3$). However, the observed antiferromagnetic (AF) order questions this viewpoint. In this work, we present first-principles calculations and find that while the 1NN Ni${}^{2+}$-Ir${}^{6+}$ exchange is indeed FM, the 2NN and 3NN couplings in the fcc Ir (and Ni) sublattice are AF. Moreover, the 2NN AF Ir-Ir coupling turns out to be even stronger than the 1NN FM Ni-Ir coupling, thus giving rise to a magnetic frustration. Sr${}_2$NiIrO${}_6$ hence becomes a distorted low-temperature antiferromagnet. Naturally, a very similar magnetic property in Sr${}_2$ZnIrO${}_6$ can be explained by the frustrated AF coupling in the fcc Ir${}^{6+}$ sublattice. This work highlights the long-range magnetic interaction of the delocalized $5d$ electrons, and also addresses why the spin-orbit coupling is ineffective here.

5 pages, 5 figures, 1 table

References in corpus (5)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Novel Jeff = 1/2 Mott State Induced by Relativistic Spin-Orbit Coupling in Sr2IrO4
• Ab-inito study of low temperature magnetic properties of double perovskite Sr2FeOsO6
• Theory of High T${}_c$ Ferrimagnetism in a Multi-orbital Mott Insulator
• Ferrimagnetism in the double perovskite Ca2FeOsO6: a density functional study

Cited by in corpus (3)

• Contrasting electronic states of RuI3 and RuCl3
• Magnetic frustration in the cubic double perovskite Ba2NiIrO6
• Crystal Growth of a New 8H Perovskite Sr8Os6.3O24 Exhibiting High TC Ferromagnetism