Influence on Dielectric Property

Abstract

Solid solutions of Pd[(ZrxTi_1-x)_1-y(Mg_1/2W_1/2)_y]O3(PZTMW) were prepared from mixed powders of raw oxides with different degrees of mixing. A relation between their compositional fluctuation (inhomogeneity of composition) and dielectric property was investigated. The mixed powders whose average composition corresponded to PZTMW ((x, y) = (0.2, O.2))were prepared by following three ways respectively. ( 1 ) All component oxides were mixed thoroughly with an agate mortar and a pestle (MIXTURE-1). ( 2 ) Four kinds of mixed powders with the compositions of (x, y) = (0.1, 0.1), (0.1, 0.3), (0.3, 0.1), (0.3, 0.3)respectively were prepared in the same way as (1). Equimolar amounts of them were taken and shook in a bottle (MIXTURE-2). (3) After an oxide mixture containing Zr₄₊, Ti₄₊, and Mg₂₊ was prepared by decomposition of their coprecipitates, PbO, W0₃, and this mixture were mixed thoroughly with an agate mortar and a pestle (MIXTURE-3). Each mixed powder was pressed into a pellet and fired in a PbO atmosphere at 1100°C for 1 h. The compositional fluctuation of the fired samples was observed by a measurement of angle dependence of width of X-ray powder diffraction peaks. The compositional fluctuation was observed in PZTMW from MIXTURE-1 and the larger fluctuation was observed in PZTMW from MIXTURE-2. PZTMW from MIXTURE-3 had almost no compositional fluctuation. The width of dielectric peak at the Curie temperature (Te) approximately corresponded to that calculated from the estimated compositional fluctuation.