Strong enhancement of magnetic ordering temperature and structural/valence transitions in EuPd3S4 under high pressure

• Main Authors: Huyan, S, Ryan, D. H, Slade, T. J, Lavina, B, Jose, G. C, Wang, H, Wilde, J. M, Ribeiro, R. A, Zhao, J, Xie, W, Bi, W, Alp, E. E, Bud'ko, S. L, Canfield, P. C
• Format: Journal Article
• Language: English
• Published: 28-06-2023
• Subjects: Physics - Strongly Correlated Electrons
• DOI: 10.48550/arxiv.2306.16517

Proc. Natl. Acad. Sci. 120 (52) e2310779120 (2023) 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.