X-ray and magnetic studies of Zn2+ substituted Ni-Pb ferrites

Seven samples of the polycrystalline, Ni_1.25-xZn_xPb_0.25Fe_1.5O₄ (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) ferrites, were prepared by usual double sintering ceramic method. X-ray diffraction patterns of the samples revealed single-phase cubic spinel structure. The magnetic properties were investigated by means of magnetization and a.c. susceptibility (χ) measurements. A.C. susceptibility was measured from room temperature to the Curie temperatureT _C) of the samples. Variation of a.c. susceptibility (χ) with temperature showed that the samples withx = 0.3 and 0.5 contain single-domain (SD) particles whereas the samples with x = 0.4 and 0.6 showed multi-domain (MD) nature. Values of Curie temperature ( T _C)as obtained from the study of variation of a.c. susceptibility with temperature were found to decrease with increase in the Zn ²⁺ concentration (x bd. Magnetic measurements showed increase in magnetization as Zn²⁺ content was increased from 00 to 0.5. Further increase in Zn²⁺ contentx bd reduces the magnetization.