Rare-earth—gallium—iron glasses. II. Anomalous magnetic hysteresis in alloys based on Pr, Nd, and Sm

Giant magnetic coercivity is reported in several metallic glasses of the form ${\left(R_{80}{G}_{20}\right)}_{100-x}{\mathrm{Fe}}_x$ where $R$ represents Pr, Nd, or Sm, $G$ represents Ga or Au, and $15\le x\le 30$. An unusual temperature variation of the coercive field is observed showing peaks at intermediate temperatures (≃90 K). In contrast to similar glasses based on heavy rare-earth metals, these glasses exhibit significant chemical short-range order and even phase separation as is shown by the Mössbauer effect and other measurements. The results are consistent with a recent theory which predicts that large coercivity can result from the presence of site-to-site variations in magnetic properties.