SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 52: Frustrated Magnets: Strong Spin-Orbit Coupling

TT 52.2: Vortrag

Donnerstag, 30. März 2023, 15:15–15:30, HSZ 201

Thermal decomposition of the Kitaev material α-RuCl₃ and its influence on the low-temperature properties — •Franziska Breitner¹, Anton Jesche¹, Vladimir Tsurkan², and Philipp Gegenwart¹ — ¹Experimental Physics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany — ²Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86159 Augsburg, Germany

Thermally driven decomposition and reduction of honeycomb ruthenium-trichloride has been known long before the material attracted considerable interest as a Kitaev system [1,2]. We systematically explore the effect of heat treatment in argon atmosphere under various temperatures up to 500^∘C on single crystals by study of the mass loss, microprobe energy dispersive x-ray spectroscopy, powder x-ray diffraction, as well as low-temperature magnetic susceptibility and specific heat experiments. For annealing temperatures beyond 300^∘C we detect clear signatures of dechlorination and oxidation of Ru. The specific heat is consistently described by the sum of a major α-RuCl₃ and minor RuO₂ volume fraction, whose latter C∼T contribution dominates the total specific heat below 1 K. Comparison with measurements on unannealed crystals suggests that even therein a tiny RuO₂ metal fraction cannot be excluded, which could be relevant also for other physical properties.
[1] A.E. Newkirk and D.W. McKee, J. Catal. 11, 370 (1968)
[2] J.A. Sears et al., Phys. Rev. B 91, 144420 (2015)