• Tozer, Stanley W.
• Goddard, Paul
• Coniglio, William
• Graf, David Earl
• Brown, Matthew
• Pearce, Matthew
• Singleton, John
• Coak, Matthew John
• Maple, M. Brian
• Götze, Kathrin
• Grockowiak, Audrey
• Ho, Pei-Chun

Abstract

CeOs₄Sb₁₂, a member of the skutterudite family, has an unusual semimetallic low-temperature L-phase that inhabits a wedge-like area of the field H—temperature T phase diagram. We have conducted measurements of electrical transport and megahertz conductivity on CeOs₄Sb₁₂ single crystals under pressures of up to 3 GPa and in high magnetic fields of up to 41 T to investigate the influence of pressure on the different H–T phase boundaries. While the high-temperature valence transition between the metallic H-phase and the L-phase is shifted to higher T by pressures of the order of 1 GPa, we observed only a marginal suppression of the S-phase that is found below 1 K for pressures of up to 1.91 GPa. High-field quantum oscillations have been observed for pressures up to 3.0 GPa and the Fermi surface of the high-field side of the H-phase is found to show a surprising decrease in size with increasing pressure, implying a change in electronic structure rather than a mere contraction of lattice parameters. We evaluate the field-dependence of the effective masses for different pressures and also reflect on the sample dependence of some of the properties of CeOs₄Sb₁₂ which appears to be limited to the low-field region.

Topics

• impedance spectroscopy
• surface
• single crystal
• phase
• phase diagram