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arXiv · 1504.03642

High antiferromagnetic transition temperature of a honeycomb compound SrRu$_2$O$_6$

W. Tian·C. Svoboda·M. Ochi·M. Matsuda·H. B. Cao·J. -G. Cheng·B. C. Sales·D. G. Mandrus·R. Arita·N. Trivedi·J. -Q. Yan
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Abstract

The high temperature magnetic order in SrRu$_2$O$_6$ was studied by measuring magnetization and neutron powder diffraction with both polarized and unpolarized neutrons. SrRu$_2$O$_6$ crystallizes into the hexagonal lead antimonate (PbSb$_2$O$_6$, space group \textit{P}$\overline{3}$1\textit{m}) structure with layers of edge-sharing RuO$_6$ octahedra separated by Sr$^{2+}$ ions. SrRu$_2$O$_6$ orders at $T_N$=565\,K with Ru moments coupled antiferromagnetically both in-plane and out-of-plane. The magnetic moment is 1.30(2) $μ_\mathrm{B}$/Ru at room temperature and is along the crystallographic \textit{c}-axis in the G-type magnetic structure. We performed density functional calculations with constrained RPA to obtain the electronic structure and effective intra- and inter-orbital interaction parameters. The projected density of states show strong hybridization between Ru 4$d$ and O 2$p$. By downfolding to the target $t_{2g}$ bands we extracted the effective magnetic Hamiltonian. We performed Monte Carlo simulations to determine the transition temperature as a function of inter- and intra-plane couplings and find weak inter plane coupling, 3\% of the intra-plane coupling, permits three dimensional magnetic order at $T_N$. As suggested by the magnetic susceptibility, two-dimensional correlations persist above $T_N$ due to the strong intra-plane coupling.

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W. Tian, C. Svoboda, M. Ochi, M. Matsuda, H. B. Cao, J. -G. Cheng, B. C. Sales, D. G. Mandrus, R. Arita, N. Trivedi, J. -Q. Yan. 2015-04-14. High antiferromagnetic transition temperature of a honeycomb compound SrRu$_2$O$_6$. https://doi.org/10.1103/physrevb.92.100404

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