Effect of heat treatment on microwave absorption properties of Ni-Zn-Mg-La ferrite nanoparticles

Spinel structure Ni-Zn-Mg-La ferrites have been prepared by the sol-gel route and investigated as a radar absorbing material (RAM) in a frequency range of 1-18 GHz. The structure and morphological studies on the nanoparticles of the ferrites have been carried out using X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The complex permeability and complex permittivity are measured by a network analyzer. The electromagnetic wave loss and microwave absorbing property are studied as a function of frequency, annealing temperature and thickness of the absorber. The results indicate that electromagnetic wave loss of the ferrite only annealed at 850 degrees C shows two peaks. The reflection loss varies with the change of the annealing temperature. The absorber annealed at 850 degrees C exhibits the best microwave absorbing properties, which is suitable for microwave absorption materials. (C) 2013 Elsevier B.V. All rights reserved.