Modified composition of barium ferrite to act as a microwave absorber in X-band frequencies

The magnetic and electromagnetic wave absorbing properties of the Co-Mn-Ti substituted barium ferrites, BaCoxMnxTi2xFe12-4xO4 (0 <= x >= 0.5), prepared by a solid-state technique, were investigated. The grain size uniformity and densification improved with increasing concentration of Co-Mn-Ti, while the permeability increased and the coercivity decreased remarkably. The reflection coefficients (S-11, S-12) of the ferrite samples were measured in the X-band frequency range (8-12 GHz) and their absorbing properties were calculated according to transmission line theory. The maximum reflection loss (-14.7 dB) is observed for the x = 0.4 sample. A ferromagnetic resonance frequency shift has been observed to depend on the Co-Mn-Ti concentration, which is an important phenomenon of barium territe for absorbing microwaves at high frequencies. Based on the magnetic and microwave measurements, BaCoxMnxTi2xFe12-4xO4 may be a good potential candidate for electromagnetic compatibility and for other practical applications at high frequencies. (C) 2009 Elsevier Ltd. All rights reserved.