Study the Structural and Dielectric Properties of Rare-Earth La Doped (Ba1-xLax) (Ti0.815Mn0.0025Nb0.0025Zr0.18)(0.995)O-3 Ceramics

摘要

The ferroelectric La doped (Ba1-xLax) (Ti0.815Mn0.0025Nb0.0025Zr0.18)(0.995)O-3 (BLTMNZ) (where x = 0.04, 0.10 and 0.20) ceramics were prepared by using the solid state reaction method. The powders in the suitable stoichiometric ratio of the compositions were weighed and mixed thoroughly in acetone and calcined at 900 degrees C for 12h in high temperature muffle furnace. Phase identification of ceramics was carried out in 2 range of 20 degrees-60 degrees using X-ray diffraction technique. XRD pattern of the samples indicated that the compositions have an orthorhombic structure at room temperature. The average crystallite size of the BLTMNZ particle was found near 30nm. The ferroelectric phase-transition of BLTMNZ materials was studied by using dielectric measurements at different temperature. Dielectric constant and tan of the specimens was measured in the temperature range from 23 degrees C to200 degrees C at frequencies 1kHz-1MHz. The temperature dependence of dielectric measurement of lanthanum doped BLTMNZ samples indicate that the phase transition shifts towards low temperature with increasing La content. The value of diffusivity (gamma) indicates that the compounds exhibit a diffuse type of phase transition. The ac conductivity was decreases with the increasing the frequency.