# Spin waves and spin-state transitions in a ruthenate high-temperature antiferromagnet

## TL;DR

This paper introduces a new RIXS technique to study collective magnetic excitations in microcrystals of 4d transition-metal compounds, revealing insights into spin waves and spin-state transitions in SrRu₂O₆, an antiferromagnet with high Nel temperature.

## Contribution

A novel RIXS method is developed to probe collective modes in microcrystals, advancing the understanding of magnetism in 4d transition-metal oxides like SrRu₂O₆.

## Key findings

- Observed spin waves and spin-state transitions in SrRu₂O₆
- Provided momentum-resolved spectroscopy of 4d transition-metal compounds
- Gained new insights into the unconventional magnetism of SrRu₂O₆

## Abstract

Ruthenium compounds play prominent roles in materials research ranging from oxide electronics to catalysis, and serve as a platform for fundamental concepts such as spin-triplet superconductivity, Kitaev spin-liquids, and solid-state analogues of the Higgs mode in particle physics. However, basic questions about the electronic structure of ruthenates remain unanswered, because several key parameters (including the Hund's-rule, spin-orbit, and exchange interactions) are comparable in magnitude, and their interplay is poorly understood - partly due to difficulties in synthesizing sizable single crystals for spectroscopic experiments. Here we introduce a resonant inelastic x-ray scattering (RIXS) technique capable of probing collective modes in microcrystals of $4d$-electron materials. We present a comprehensive set of data on spin waves and spin-state transitions in the honeycomb antiferromagnet SrRu$_{2}$O$_{6}$, which possesses an unusually high N\'eel temperature. The new RIXS method provides fresh insight into the unconventional magnetism of SrRu$_{2}$O$_{6}$, and enables momentum-resolved spectroscopy of a large class of $4d$ transition-metal compounds.