Characterization and low-temperature sintering of Ni0.5Zn0.5Fe2O4 nano-powders prepared by refluxing method

The as-prepared Ni0.5Zn0.5Fe2O4 powders fabricated directly from the solution of metal nitrates by the refluxing method were testified by the analysis of XRD, TEM, SAED and HRTEM. XRD pattern indicated that obtained Ni0.5Zn0.5Fe2O4 powders were single phase with spinel structure, TEM analysis showed that the powders with cubic shape were uniform in particle size of about 10-20 nm. Ceramics prepared by the assynthesized Ni0.5Zn0.5Fe2O4 powders sintered at various temperatures between 950 degrees C and 1150 C for 2 h were observed by SEM technique, which indicated that the Ni0.5Zn0.5Fe2O4 ferrites can almost be sintered to theoretic density at 1100 degrees C for 2 h, lower by at least about 200 degrees C compared with those ferrites prepared by the conventional oxide method. The relative magnetic loss tan delta/mu(i) of the ceramic samples sintered at the temperature 1050 degrees C was measured to be of the order of 10(-4)-10(-5) in the frequency range from 1 MHz to 10 MHz, and the threshold frequency of the ferrites was 77.2 MHz. (c) 2008 Published by Elsevier B.V.