J. Phys. IV France 128 (2005) 133-137
Dielectric behavior of lead iron tantalate - lead titanate ceramicsD. Szwagierczak, J. Kulawik and B. Gröger
Institute of Electron Technology, Cracow Division, Cracow, Poland
Dielectric properties of complex perovskite Pb(Fe1/2Ta1/2)O3 (PFT) and its solid solutions with normal ferroelectric PbTiO3 (PT) were studied. The addition of 5 - 25 mol % of PbTiO3 was used to shift upwards the temperature of the ferroelectric-paraelectric transition of pure PFT. Dielectric permittivity and dissipation factor of the ceramics were determined in the temperature range from -55 to 550 C at frequencies 10 Hz - 1 MHz. Dc resistivities of the samples were measured in the temperature range 20 - 500 C. The PFT-based ceramics sintered at 1050 C showed a relatively high dielectric permittivity (3000 - 5700 at Curie temperature) and a high resistivity (1011 - 10 cm at 20 C). Two broad maxima in the dielectric permittivity versus temperature plots were observed at a given frequency. The location of the first one, corresponding to the ferroelectric - paraelectric transition, changed from -30 C for pure PFT to 80 C for 0.75PFT-0.25PT ceramics. The second maximum, related to dielectric relaxation, occurred at higher temperatures in the range 200 - 500 C and was strongly dependent on frequency and the content of dopants.
© EDP Sciences 2005