Microstructure and Dielectric Tunable Properties of Al_2O_3-doped Barium Strontium Titanate in the Paraelectric State
顺电态下掺铝钛酸锶钡陶瓷微结构和介电调谐性能

Al2O3-doped Ba0.6Sr0.4TiO3(BST) ceramics were prepared by using conventional ceramic technology. The samples were analysed by SEM and XRD. The results indicate that Al3+ behaves as a grain-growth helper below a certain doping level and also the dopants have entered the unit-cell maintaining the perovskite structure of the solid solution. The dielectric constant and dissipation factor decrease and the tunability increases by addition of Al2O3. The specimen at doping level of 0.8wt% has the optimal overall dielectric properties.