The influences of mole composition of strontium (x) on properties of barium strontium titanate (Ba_1−xSr_xTiO₃) prepared by solid state reaction method

Barium Strontium Titanate (Ba_1-xSr_xTiO₃) or BST was prepared by solid state reaction method. Raw materials are BaCO₃, SrCO₃, and TiO₂. Those materials are mixed for 8 h, pressed, and sintered at temperature 1200°C for 2 h. Mole composition of Sr (x) was varied to study its influences on structural, morphological, and electrical properties of BST. Variation of (x) are x = 0; x = 0.1; and x = 0.5. XRD patterns showed a single phase of BST, which mean that mixture of raw materials was homogenous. Crystal structure was influenced by x. BaTiO₃ and Ba_0.9Ti_0.1TiO₃ have tetragonal crystal structure, while Ba_0.5Sr_0.5TiO₃ is cubic. The diffraction angle shifted to right side (angle larger) as the increases of x. Crystalline size of BaTiO₃, Ba_0.9Sr_0.1TiO₃, and Ba_0.5Sr_0.5TiO₃ are 38.13 nm; 38.62 nm; and 37.13 nm, respectively. SEM images showed that there are still of pores which were influenced by x. Ba_0.9Sr_0.1TiO₃ has densest surface (pores are few and small in size). Sawyer Tower circuit showed that BaTiO₃ and Ba_0.9Sr_0.1 TiO₃ is ferroelectric, while Ba_0.5Sr_0.5TiO₃ is paraelectric. The dielectric constants of BaTiO₃, Ba_0.9Sr_0.1TiO₃ and Ba_0.5Sr_0.5TiO₃ at frequency of 1 KHz are 156; 196; and 83, respectively. Ba_0.9Sr_0.1TiO₃ has relatively highest dielectric constant. It is considered that Ba_0.9Sr_0.1TiO₃ has densest surface