Studies on Structural and Dielectric Properties of CMFO Ferrite and BZT Ferroelectric Magnetoelectric Composites

In the present work, the frequency and temperature dependant dielectric properties of (x) Co1.2-yMnyFe1.8O4 + (1-x) BaZr0.08Ti0.92O3 magnetoelectric composites were studied. The magnetostrictive (ferrite) phase, Co1.2-yMnyFe1.8O4 with y = 0.0 to 0.4 (CMFO) was synthesized by combustion route and the piezoelectric phase, BaZr0.08Ti0.92O3 (BZT) was synthesized by conventional ceramic route. These individual prepared phases were combined by ceramic method to obtain the magnetoelectric (ME) composites. Room temperature dielectric constant measurements as a function of frequency, shows the usual dielectric dispersion behaviour, which may be attributed to the Maxwell- Wagner type of interfacial polarization. Dielectric constant measurements with temperature shows the two dielectric maxima, one at below 100 degrees C and the second at above 500 degrees C, the dielectric maxima below 100 degrees C corresponds to the transition temperature of ferroelectric phase and that of above 500 degrees C corresponds to the transition temperature of ferrite phase of the ME composites. From these dielectric constant measurements, it was observed that as the Mn content increases, the phase transition temperature goes on decreasing. The ac conductivity measurements in the frequency range from 20 Hz to 1MHz were also performed to study the conduction mechanism in the composites.