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Giant magnetic coercivity is reported in several metallic glasses of the form (R80G20)100-xFex where R represents Pr, Nd, or Sm, G represents Ga or Au, and 15≤x≤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.