Frequency and temperature dependent electrical properties of Ni0.7Zn0.3CrxFe2-xO4 (0 ≤ x ≤ 0.5)

Series of the ferrite samples with a chemical formula Ni0.7Zn0.3CrxFe2-xO4 = 0.0-0.5) were prepared by a sol-gel auto-combustion method and annealed at 600 degrees C for 4 h. The prepared samples have the cubic spinel structure with no impurity phase. As the Cr3+ content x increases, the unit cell dimensions decrease with an increase in Cr3+ content x. The crystallite size is decreases from 37 nm to 21 nm as the Cr3+ content increases from x = 0.0 to 0.5. Resistivity increases whereas dielectric constant decreases with an increase in Cr3+ content x. Maxima in the dielectric loss tangent versus frequency appear when the frequency of the hopping charge carriers coincides with the frequency of the applied alternating field. Dielectric constant and dielectric loss tangent increases with increase in temperature. Saturation magnetization of sintered samples showed higher values as compared to as-prepared sample. Curie temperature deduced from AC susceptibility data decreases with increasing x. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.