Ferrimagnetism in the double perovskite Ca2FeOsO6: a density functional study

Abstract

Using density functional calculations, we find that the newly synthesized Ca${}_2$FeOsO${}_6$ has the high-spin Fe${}^{3+}$ ($3d^5$)-Os${}^{5+}$ ($5d^3$) state. The octahedral Os${}^{5+}$ ion has a large intrinsic exchange splitting, and its $t_{2g\uparrow }^3$ configuration makes the spin-orbit coupling ineffective. Moreover, there is a strong antiferromagnetic (AF) coupling between the neighboring Fe${}^{3+}$ ($S$ = 5/2) and Os${}^{5+}$ ($S$ = -3/2), but the AF couplings within both the fcc Fe${}^{3+}$ and Os${}^{5+}$ sublattices are one order of magnitude weaker. Therefore, a magnetic frustration is suppressed and a stable ferrimagnetic (FiM) ground state appears. This FiM order is due to the virtual hopping of the $t_{2g}$ electrons from Os${}^{5+}$ ($t_{2g\downarrow }^3$) to Fe${}^{3+}$ ($t_{2g\uparrow }^3{e}_{g\uparrow }^2$). However, if the experimental bended Fe${}^{3+}$-O${}^{2-}$-Os${}^{5+}$ exchange path gets straight, the $e_g$ hopping from Fe${}^{3+}$ ($t_{2g\uparrow }^3{e}_{g\uparrow }^2$) to Os${}^{5+}$ ($t_{2g\uparrow }^3$) would be facilitated and then a ferromagnetic (FM) coupling would occur.

5 pages, 5 figures

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• 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
• Theory of High T${}_c$ Ferrimagnetism in a Multi-orbital Mott Insulator

Cited by in corpus (6)

• Predicting a Ferrimagnetic Phase of Zn2FeOsO6 with Strong Magnetoelectric Coupling
• Ba2NiOsO6: A Dirac-Mott insulator with ferromagnetism near 100 K
• Long-range magnetic interaction and frustration in double perovskite Sr${}_2$NiIrO${}_6$
• The role of nonmagnetic d0 vs. d10 B-type cations on the magnetic exchange interactions in osmium double perovskites
• Magnetic frustration in the cubic double perovskite Ba2NiIrO6
• Spin-Orbital States and Strong Antiferromagnetism of Layered Eu${}_2$SrFe${}_2$O${}_6$ and Sr${}_3$Fe${}_2$O${}_4$Cl${}_2$