Microstructure, Magnetic and Dielectric Properties of CoFe2O4–Pb(Fe1/2Ta1/2)O3-PbTiO3 Composites
The paper reports on bulk and layered multiferroic composites based on cobalt ferrite and lead iron tantalate-lead titanate solid solution. Syntheses of CoFe2O4 and Pb(Fe1/2Ta1/2)O3 were performed by conventional solid state reactions. 0.5CoFe2O4–0.425Pb(Fe1/2Ta1/2)O3-0.075PbTiO3 bulk composites were prepared by sintering at 900°C. Multilayer composites were fabricated by tape casting, stacking and lamination of alternate ferrite and relaxor layers, followed by cosintering at 950°C. X-ray diffraction analysis and scanning electron microscopic observations confirm that the obtained ceramic samples are composed of ferrite spinel and relaxor perovskite phases. Impedance spectroscopic studies carried out in the temperature range 218-623 K at frequencies 10 Hz–2 MHz show high and broad maxima of dielectric permittivity. On the basis of investigations of magnetization versus magnetic field (up to 85 kOe) and temperature (4-400 K), the behavior typical of hard magnetic materials was found for CF-PFT-PT composites. The measurements carried out at room temperature as a function of the external dc magnetic field and frequency of the sinusoidal ac modulation field, reveal a distinct magnetoelectric effect of the investigated bulk and layered composites.
Pietro VINCENZINI, Vojislav V. MITIC, Alois LOIDL and Dino FIORANI
J. Kulawik et al., "Microstructure, Magnetic and Dielectric Properties of CoFe2O4–Pb(Fe1/2Ta1/2)O3-PbTiO3 Composites", Advances in Science and Technology, Vol. 67, pp. 158-163, 2010