2022 年 32 巻 1 号 p. 3-11
In this article, we review high-pressure nuclear magnetic resonance studies on SmS, a prototypical intermediate valence compound, which was achieved using a 33S-enriched sample. A resonance arising from the magnetically ordered phase has been for the first time observed below 15-20 K above a nonmagnetic-magnetic transition pressure Pc2 ≈ 2 GPa. We have obtained information on the first-order nature of the transition. Also, the screening of the localized character of Sm-4f electrons is suggested, which may require an understanding beyond the conventional framework for heavy fermions. From the fact that spontaneous internal fields cancel out at the S site leads, we conclude that the ordered phase has a type II antiferromagnetic structure.
