Magnetic, electrical and dielectric behaviour of Ni0.8Zn0.2Fe2O4 prepared through flash combustion technique

Nickel-zinc ferrites of composition Ni0.8Zn0.2Fe2O4 were prepared by flash combustion technique and sintered at various sintering temperatures such as 1150degreesC, 1250degreesC and 1350degreesC. Magnetic properties like hysteresis parameters, saturation magnetisation and Curie temperature were studied. Electrical properties namely AC-resistivity as a function of frequency and DC-resistivity as a function of temperature were studied for ferrite samples sintered at various temperatures. Dielectric properties such as dielectric constant, epsilon' and dielectric loss factor, tan delta were also studied for ferrite samples as a function of frequency. It is observed that Ni-Zn ferrites prepared by this method have AC-resistivity of the order 10(6)-10(1) Omega cm for the frequency range from 1 kHz to 13 MHz and DC-resistivity of the order greater than or equal to 10(9) Omega cm is observed as the function of temperature from room temperature to 300'C. The resistivity obtained is higher than that of ferrites prepared by the conventional ceramic method. This is because of high purity, controlled microstructure and porosity of ferrites prepared by flash combustion technique. The dielectric constant and dielectric loss obtained for the ferrites prepared through this flash combustion technique possess lower value than that of the ferrites prepared by conventional ceramic method for the same composition. High resistivity and low dielectric behaviour make these ferrite materials useful in high frequency applications. (C) 2002 Elsevier Science B.V. All rights reserved.