Abstract
We present magnetization measurements on polycrystalline under hydrostatic pressures up to 3 GPa and construct the temperature-pressure phase diagram of this material. Our data confirm that magnetic order breaks down in a first-order phase transition at GPa and additionally reveal a steplike feature—magnetic signature of structural dimerization—that appears at and shifts to higher temperatures upon further compression. Following the structural study by L. S. I. Veiga et al. [Phys. Rev. B 100, 064104 (2019)], we suggest that a partially dimerized phase with a mixture of magnetic and nonmagnetic sites develops above . This phase is thermodynamically stable between 1.7 and 2.7 GPa according to our ab initio calculations. It confines the magnetic sites to weakly coupled tetramers with a singlet ground state and no long-range magnetic order. Our results rule out the formation of a pressure-induced spin-liquid phase in and reveal peculiarities of the magnetism collapse transition in a Kitaev material. We also show that a compressive strain imposed by the pressure treatment of enhances signatures of the 100 K magnetic anomaly at ambient pressure.
3 More- Received 6 August 2021
- Revised 8 October 2021
- Accepted 12 October 2021
DOI:https://doi.org/10.1103/PhysRevB.104.134426
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