Ferrite nano particles of basic composition Ni Cd Smx Fe2-xO4(0.0 ≤ x ≤ 0.05, X=0.01) where synthesized by citrate-gel auto combustion method have investigated. X-ray diffraction profile indicates that the samples are in single phase structure for the sample without Sm content. For the samples with Sm ions, some diffraction peaks appeared which belongs to the orthorhombic phase structure further, the XRD have been used calculated the lattice parameter, density and grain size. The particle size of the starting powder composition varied from 30 nm to 45 nm. The values of lattice parameter (a) decreased and X-ray density (dx) increased with the increase of Sm content. Morphology of the prepared samples by citrate-gel method was studied using scanning electron microscope (SEM). The elemental analysis of all the Ni-Cd-Sm ferrite samples with different compositions was analyzed by Energy Dispersive Spectrometer (EDS). The observed results can be explained on the basis of composition and crystal size.