On the nature of the disordered microstructure in Sm(Co,Cu)5 alloys with increasing Cu content

X-ray diffraction and transmission electron microscopy (TEM) experiments were performed in heat-treated Sm(Co,Cu)5 samples with different Co/Cu content. The major phase observed in the diffraction patterns exhibits a hexagonal CaCu5 type structure in all the studied compositions. The behavior of the diffraction profiles, as function of the Cu content, is believed to be due to an inhomogeneous distribution of Co and Cu through out the samples. Heavily planar faulted regions have been observed by means of TEM and are also associated with Sm and Co rich phases within the matrix. A CaCu5 type structure with local Sm rich regions seems to be responsible for the observed magnetic behavior.