Pressure-induced magnetic phase transition in gold-phase SmS

Abstract

Electrical resistivity and specific heat of SmS in its gold phase have been investigated. Above ${P}_{\ensuremath{\Delta}}=2\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$, the resistivity is characteristic of a metallic heavy fermion compound. Ac calorimetry points out a phase transition with the occurrence of a new ground state. Analyses of the resistivity and of the specific heat and comparison with a microscopic probe ($^{149}\mathrm{Sm}$ nuclear forward scattering) allow us to identify the onset of antiferromagnetism. Discussion will be made on the interplay of gap closing $(P<{P}_{\ensuremath{\Delta}})$, long-range magnetism $(P>{P}_{\ensuremath{\Delta}})$, and valence state.