Flat profile of permittivity vs temperature for graded Ba1-xSrxTiO3 ceramics

Graded Ba1-xSrxTiO3 (BST) ceramics, which had a continuously varying graded composition from one surface toward the other of the specimen, were examin ed with respect to their dielectric property. Specimens were prepared by si ntering superposed layers of green compacts of BST solid solutions with dif ferent values of x. The electric relative permittivity of a single phase BS T ceramic showed a peak at the Curie temperature, which shifted to lower te mperatures with increasing x. On the other hand, the profile of relative pe rmittivity vs temperature of the graded BST ceramic experienced a linear ch aracteristic. Furthermore, its slope could be controlled by changing the vo lume fraction of each layer. The relative permittivity was 4000-5500 +/- 5% in the temperature range from 30 to 110 degreesC.