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Abstract
Polycrystalline ferrite samples having the general formula Co(1-x) Zn(x) Fe(2-y) SmyO4 (where x= 0.0,0.2,0.4) were prepared by conventional standard ceramic technique. The single-phase cubic spinel structures of the samples were confirmed by x-ray diffraction patterns. It seems that substituted Sm3+ decreases the lattice constant by small extent and increases x-ray density. The hoping lengths LA, LB and bond lengths dAx, dBx are found varying as per changes in lattice constant. The cation distribution shows that non-magnetic Zn2+ occupies A-site. Ni2+ and Sm3+ are found to be diverting towards B-site. The substitution of Sm3+ increases the electrical resistivity of ferrites. The resistivity decreases with increasing temperature. Curie temperature obtained by d. c. resistivity are in good agreements with those obtained by a. c. susceptibility. Activation energies are found greater in paramagnetic region than those in ferrimagnetic region.