Effect of Sm3+ substitution on the structural and magnetic properties of Ni-Co nanoferrites

Samarium doped nanoferrites Ni0.5Co0.5SmxFe2-xO4 with (x = 0.00, 0.025, 0.05, 0.075, 0.10, 0.125) samples were prepared by using auto-combustion route. XRD pattern analysis confirmed the single-phase cubic spinel structure with no evidence of secondary phase. It is observed that, the lattice constant decreased from 8.342 angstrom (x=0) to 8.321 angstrom (0.100) and again increased to 8.370 for x = 0.125. The crystallite size and particle size indicate the nano sized . nature of the prepared ferrites. Crystalite size varies nonlinearly between 33 nm and 25 nm with addition of Sm3+ content in Ni-Co nanoferrites. The agglomerated grain structure revealed the high surface interaction among magnetic nanoparticles. FTIR spectra revealed the characteristics features of ferrite skeleton formation. The saturation magnetization, coercivity and remanence magnetization are found to decreases with the substitution of Sm3+ ions.