Pressure-induced magnetic phase transition in gold-phase SmS

Electrical resistivity and specific heat of SmS in its gold phase have been investigated. Above P-Delta=2 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 (Sm-149 nuclear forward scattering) allow us to identify the onset of antiferromagnetism. Discussion will be made on the interplay of gap closing (PP-Delta), and valence state.