Journal Article

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

Minola, M, Sears, J A, H-C, Wille, Khaliullin, G, Kukusta, D, Gretarsson, H, Yang, Z, Kim, B J, Takagi, H, Kim, H, Yavaş, H, Liu, H, Ueda, K, Yaresko, A, Suzuki, H, Keimer, B, Nuss, J, Francoual, S, Ishikawa, H

2019

Overview

Ruthenium compounds serve as a platform for fundamental concepts such as spin-triplet superconductivity1, Kitaev spin liquids2–5 and solid-state analogues of the Higgs mode in particle physics6,7. However, basic questions about the electronic structure of ruthenates remain unanswered, because several key parameters (including Hund’s coupling, spin–orbit coupling and exchange interactions) are comparable in magnitude and their interplay is poorly understood, partly due to difficulties in synthesizing large single crystals for spectroscopic experiments. Here we introduce a resonant inelastic X-ray scattering (RIXS)8,9 technique capable of probing collective modes in microcrystals of 4d electron materials. We observe spin waves and spin-state transitions in the honeycomb antiferromagnet SrRu2O6 (ref. 10) and use the extracted exchange interactions and measured magnon gap to explain its high Néel temperature11–16. We expect that the RIXS method presented here will enable momentum-resolved spectroscopy of a large class of 4d transition-metal compounds.Resonant inelastic X-ray scattering at the 4d-edge reveals dispersive magnetic excitations in SrRu2O6, providing insight into the origin of its high Néel temperature.

• Publisher: Nature Publishing Group
• Subject: Antiferromagnetism / Crystals / Electron spin / Electronic structure / Energy / Exchanging / Experiments / High temperature / Inelastic scattering / Magnons / Metal compounds / Microcrystals / Physics / Ruthenium / Ruthenium compounds / Single crystals / Spectrum analysis / Spin-orbit interactions / Transition metal compounds / X-ray scattering / X-rays