Structural, electrical transport, and magnetic properties of Ni1-xZnxFe2O4

Structural, electrical, and magnetic properties of Ni1-xZnxFe2O4 (x = 0.2, 0.4) samples sintered at various temperatures have been investigated thoroughly. The bulk density of the Ni0.8Zn0.2Fe2O4 samples increases as the sintering temperature (T-s) increases from 1200 to 1300 degrees C and above 1300 degrees C the bulk density decreases slightly. The Ni0.6Zn0.4Fe2O4 samples show similar behavior of changes to that of Ni0.8Zn0.2Fe2O4 samples, except that the bulk density is found to be the highest at 1350 degrees C. The DC electrical resistivity, rho(T), decreases as the temperature increases indicating that the samples have semiconductor-like behavior. As the Zn content increases, the Curie temperature (T-c), resistivity, and the activation energy decrease while the magnetization, initial permeability, and the relative quality factor (Q) increases. A Hopkinson peak is obtained near T-c in the real part of the initial permeability vs. temperature curves. The ferrite with higher permeability has a relatively lower resonance frequency. The initial permeability and magnetization of the samples has been found to correlate with density, average grain sizes. Possible explanation for the observed structural, magnetic, and changes of resistivity behavior with various Zn content are discussed. (C) 2006 Elsevier B.V. All rights reserved.