The (SmZr)Co $_3$ Phase in Sm(CoFeCuZr) $_rm z$ Magnets

Detailed microstructural characterization of magnets and homogenized as-cast alloys, which included X-ray diffraction Rietveld analysis, has indicated that the so-called platelet or lamellae phase is (SmZr) 1 (CoFeCu) 3 with the PuNi 3 structure and lattice parameters a~0.5 nm and c~2.4 nm. The structural and magnetic properties of the (SmZr)Co 3 phase were investigated. The microstructure shows two phases differing in their Zr/Sm ratio. Magnetization curves for the samples (Sm 0.33 Zr 0.67 )Co 3 , (Sm 0.33 Zr 0.67 )Co 2.97 Fe 0.03 , and (Sm 0.67 Zr 0.33 )Co 3 are consistent with the two-phase microstructure observed. Room temperature coercivity values of these samples are low (ap1 kOe.)