Studies on dielectric and magnetoelectric behavior of 25% CMFO ferrite and 75% BZT ferroelectric multiferroic magnetoelectric composites

In the present work, multiferroic magnetoelectric (ME) composites of ferrite and ferroelectric phases are prepared. Here, the magnetostrictive (ferrite) phase, Co_1.2 − yMn_yFe_1.8O₄ (y = 0.0 to 0.4) i.e. CMFO is synthesized by chemical combustion route and the piezoelectric (ferroelectric) phase, BaZr_0.08Ti_0.92O₃ i.e. BZT is synthesized by conventional ceramic method. Frequency dependent dielectric constant measurement from 20 Hz-1 MHz at room temperature shows usual dielectric dispersion behaviour, which may be attributed to the Maxwell-Wagner type interfacial polarization. Temperature dependent dielectric constant measurement shows two dielectric maxima, one below 100 °C and the second above 500 °C. The dielectric maxima below 100 °C corresponds to the transition temperature of the ferroelectric phase and that of above 500 °C corresponds to the transition temperature of the ferrite phase of the ME composites. It is observed that as Mn content increases in the cobalt ferrite, the phase transition temperature of the ferrite phase decreases. The static magnetoelectric voltage coefficient was measured as a function of intensity of the applied dc magnetic field. These magnetoelectric composites may have possible applications in magnetic field sensing probes and linear ME devices.