Particle size dependent high frequency dielectric properties of barium titanate

Dielectric measurements on BaTiO/sub 3/ ceramics and BaTiO/sub 3/ powder-polypropylene composites were carried out through microwave frequencies using various techniques. Ceramic BaTiO/sub 3/ exhibited a large relaxation with a peak in the loss occurring at 776 MHz. Dielectric dispersion was also evident in the composites fabricated with /spl sim/1 /spl mu/m TAM HPB BaTiO/sub 3/ powder, which exhibited a peak in loss at 1.58 GHz. Composites fabricated with /spl sim/0.1 /spl mu/m Cabot BT-8 hydrothermal powder, showed a broad relaxation over the measured frequency range. The reduction in particle size and subsequent modulation of the domain structure has been attributed to the shift in the relaxation frequency.