We present a comprehensive study of the mixed valent compound, EuPd3S4, by electrical transport, X-ray diffraction, time-domain 151Eu synchrotron M\"ossbauer spectroscopy, and X-ray absorption spectroscopy measurements under high pressure. The electrical transport measurements show that the antiferromagnetic ordering temperature, TN, increases rapidly from 2.8 K at ambient pressure to 23.5 K at ~19 GPa and plateaus between ~19 and ~29 GPa after which no anomaly associated with TN is detected. A pressure-induced first order structural transition from cubic to tetragonal is observed, with a rather broad coexistence region (~20 GPa to ~32 GPa) that corresponds to the TN plateau. M\"ossbauer spectroscopy measurements show a clear valence transition from approximately 50:50 Eu2+:Eu3+ to fully Eu3+ at ~28 GPa, consistent with the vanishing of the magnetic order at the same pressure. X-ray absorption data show a transition to a fully trivalent state at a similar pressure. Our results show that pressure first greatly enhances TN, most likely via enhanced hybridization between the Eu 4f states and the conduction band, and then, second, causes a structural phase transition that coincides with the conversion of the europium to a fully trivalent state.
@article{arxiv.2306.16517,
title = {Strong enhancement of magnetic ordering temperature and structural/valence transitions in EuPd3S4 under high pressure},
author = {S. Huyan and D. H. Ryan and T. J. Slade and B. Lavina and G. C. Jose and H. Wang and J. M. Wilde and R. A. Ribeiro and J. Zhao and W. Xie and W. Bi and E. E. Alp and S. L. Bud'ko and P. C. Canfield},
journal= {arXiv preprint arXiv:2306.16517},
year = {2024}
}
Comments
28 pages, 6 figures in main manuscript, 10 figures in SI