Structural and dielectric properties of cobalt-copper ferrite/barium-strontium titanate composites

Ferromagnetic Co_0.5Cu_0.5Fe₂O₄ and ferroelectric Ba_0.8Sr_0.2TiO₃ composite ceramics, xCo_0.5Cu_0.5Fe₂O₄ + (1-x)Ba_0.8Sr_0.2TiO₃ for x = 0.15, 0.3 and 0.45, were prepared by a conventional solid-state reaction method. The crystalline phases of the sintered samples were studied by the X-ray diffraction technique. Scanning electron microscopy (SEM) micrographs were taken to understand the microstructure of the samples. Variation of dielectric constant and loss tangent were determined with temperature (room temperature to 600degC) at different test frequencies (in the range 100 Hz-1 MHz). The maximum value of dielectric constant was observed for composite with 0.45 ferrite + 0.55 ferroelectric phase.