Co2+Ti4+ substituted Z-type barium ferrite with enhanced imaginary permeability and resonance frequency

Abstract

Co2+ Ti4+ substitution for Fe3+ in Co2 Z (Ba3 Co2 Fe24 O41) has been prepared. The crystal structure and static and high-frequency magnetic properties have been studied for Ba3 Co2+x Tix Fe24-2x O41 and the corresponding ferrite/polymer composites. As compared to the general Co2 Z ferrite/polymer composite, the CoTi substituted ferrite/polymer composite with x=1.0 has a high natural resonance frequency (4.5 GHz), due to its large out-of-plane anisotropy fields Hθ. Furthermore, the maximum imaginary permeability μmax″ is increased by about 50%. The increase is attributed to a decreased damping coefficient, based on the curve-fitted results to the complex permeability spectra. The composites are good electromagnetic attenuation materials with low reflectivity and broad bandwidth at microwave frequencies. © 2006 American Institute of Physics.