Absence of magnetic order in RuO2: insights from μSR spectroscopy and neutron diffraction

作者：Philipp Keßler, Laura Garcia-Gassull, Andreas Suter, Thomas Prokscha, Z. Salman, D. D. Khalyavin, Pascal Manuel, Fabio Orlandi, I. I. Mazin, Roser Valentí, Simon Moser · 发表于：npj Spintronics · 年份：2024 · DOI：10.1038/s44306-024-00055-y · 被引用次数：120 · 研究领域：Advanced Condensed Matter Physics、Solid-state spectroscopy and crystallography、Chemical Synthesis and Characterization

Abstract Altermagnets are a novel class of magnetic materials, where magnetic order is staggered both in coordinate and momentum space. The metallic rutile oxide RuO2, long believed to be a textbook Pauli paramagnet, recently emerged as a putative workhorse altermagnet when resonant X-ray and neutron scattering studies reported nonzero magnetic moments and long-range collinear order. While some experiments seem consistent with altermagnetism, magnetic order in RuO2remains controversial. We show that RuO2is nonmagnetic, both in bulk and thin film. Muon spectroscopy complemented by density-functional theory finds at most 1.14 × 10−4 μB/Ru in bulk and at most 7.5 × 10−4 μB/Ru in 11 nm epitaxial films, at our spectrometers’ detection limit, and dramatically smaller than previously reported neutron results that were used to rationalize altermagnetic behavior. Our own neutron diffraction measurements on RuO2single crystals identify multiple scattering as the source for the false signal in earlier studies.