THERMOELECTRIC PROPERTIES OF (CuTi) SUBSTITUTED Ni-Zn FERRITES

Abstract

A series of Ni0.8 Zn0.2 Cux Tix Fe2-2x O4 ferrites with x = 0.0, 0.2, 0.4, 0.6, 0.8 were prepared by ceramic sintering method. The presence of an f.c.c phase has been confirmed by x-ray diffraction. The variation of lattice constant vs. CuTi concentration shows a large positive deviation from the Vegard’s law. Values of room temperature resistivity show a minimum at x = 0, that may be due to the hopping of electron between the ions Fe2+ ⇔ Fe3+ and Cu2+ ⇔ Cu1+. Above x = 0 the resistivity increases at higher (CuTi) concentration due to Ti4+ ions that act as scattering centers at B-sites. Seebeck coefficient (α) was measured and it shows that the samples are degenerate type semiconductors.