Pressure-induced Nonmagnetic–Magnetic Transition in SmS Observed by ³³S-NMR

Abstract

Intermediate valence compound SmS, which undergoes a nonmagnetic-magnetic transition at P c ∼ 2 GPa, has been studied by nuclear magnetic resonance (NMR) measurements at 3.2 GPa. The use of 33 S-enriched sample enabled the application of NMR technique to the study of this compound, and the measurement at the pressure well above P c was achieved using a modified opposed-anvil high pressure cell. A temperature-dependent 33 S-NMR signal arising from the paramagnetic phase shifts to an almost temperature-independent signal below about 20 K. The appearance of the lowtemperature signal is in good agreement with the pressure-induced nonmagnetic-magnetic transition reported previously, indicating the new signal originates from the magnetically ordered (MO) phase. Hyperfine field at the S site is reduced in the MO phase, suggesting that the ordered structure in the MO phase is antiferromagnetic.