Bulk hardened magnetic materials with compositions expressed by a general formula Sm.sub.u Ce.sub.1.sub.-u (Co.sub.1.sub.-x.sub.-y Fe.sub.x Cu.sub.y).sub.z are provided. Compositions in the limited range of 0.3.ltoreq.u.ltoreq.1.0, 0.ltoreq.x.ltoreq.0.1, 0.09.ltoreq.y.ltoreq.0.18, 6.0.ltoreq.z.ltoreq.7.5 lead to magnetic materials with unexpectedly large maximum energy product and with a newly found two phase structure. Magnetic materials with maximum energy product of over 13 MG.sup.. Oe (megagauss) oersted), residual induction over 7000 G and intrinsic coercive force over 3000 Oe are obtained by subjecting the compositions to a sintering process.