SmS, a prototypical intermediate valence compound, has been studied by performing high-pressure nuclear magnetic resonance measurements on a 33S-enriched sample. The observation of an additional signal below 15-20 K above a nonmagnetic-magnetic transition pressure Pc2≈2 GPa gives evidence of a magnetic transition. The absence of a Curie-term in the Knight shift near Pc2 indicates that the localized character of 4f electrons is entirely screened and the mechanism of the magnetic ordering is not described within a simple localized model. Simultaneously, the line shape in the magnetically ordered state is incompatible with a spin density wave order. These suggest that the magnetic order in SmS may require an understanding beyond the conventional framework for heavy fermions. The fact that hyperfine fields from the ordered moments cancel out at the S site leads us to a conclusion that the ordered phase has a type II antiferromagnetic structure.
@article{arxiv.2010.05539,
title = {Nonmagnetic-magnetic transition and magnetically ordered structure in SmS},
author = {S. Yoshida and T. Koyama and H. Yamada and Y. Nakai and K. Ueda and T. Mito and K. Kitagawa and Y. Haga},
journal= {arXiv preprint arXiv:2010.05539},
year = {2021}
}