The silver ruthenium oxide $\mathrm{Ag}\mathrm{Ru}{\mathrm{O}}_3$ consists of honeycomb ${\mathrm{Ru}}_2^{5+}{\mathrm{O}}_6^{2-}$ layers and can be considered an analogue of $\mathrm{Sr}{\mathrm{Ru}}_2{\mathrm{O}}_6$ with a different intercalation. We present measurements of magnetic susceptibility and specific heat on $\mathrm{Ag}\mathrm{Ru}{\mathrm{O}}_3$ single crystals, which reveal a sharp antiferromagnetic transition at 342(3) K. The electrical transport in single crystals of $\mathrm{Ag}\mathrm{Ru}{\mathrm{O}}_3$ is determined by a combination of activated conduction over an intrinsic semiconducting gap of $\approx 100$ meV and carriers trapped and thermally released from defects. From powder neutron diffraction data a Néel-type antiferromagnetic structure with the Ru moments along the $c$ axis is derived. Raman spectroscopy on $\mathrm{Ag}\mathrm{Ru}{\mathrm{O}}_3$ single crystals and muon spin rotation spectroscopy on powder samples indicate a further weak phase transition or a crossover in the temperature range 125–200 K. The transition does not show up in the magnetic susceptibility, and its origin is argued to be related to defects but cannot be fully clarified. The experimental findings are complemented by density-functional-theory-based electronic structure calculations. It is found that the magnetism in $\mathrm{Ag}\mathrm{Ru}{\mathrm{O}}_3$ is similar to that in $\mathrm{Sr}{\mathrm{Ru}}_2{\mathrm{O}}_6$, however, with stronger intralayer and weaker interlayer magnetic exchange interactions.

• Received 8 March 2021
• Accepted 17 May 2021

DOI:https://doi.org/10.1103/PhysRevB.103.214413

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Open access publication funded by the Max Planck Society.

Published by the American Physical Society