International Journal of Latest Technology in Engineering, Management & Applied Science (IJLTEMAS) Volume VI, Issue VI, June 2017 | ISSN 2278-2540 www.ijltemas.in Page 75 Effect of Different Strontium Content on Dielectric Properties of Barium Strontium Titanate Ceramic Gambheer Singh Kathait 1 , Vishal Rohilla 2 , Prashant Thapliyal 3 , Don Biswas 4 , Surendra Singh 5 1, 2, 3, 4 Assistant Professor, H.N.B. Garhwal University, Srinagar Garhwal, Uttarakhand, India 5 Research Scholar, Department of Physics, H.N.B. Garhwal University, Srinagar Garhwal, Uttarakhand, India Abstract: This paper discusses the effect of different Strontium content on the transition of Barium Strontium Titanate solid solutions. Doping of ceramics is one way to enhance the electrical properties. BST, PZT and other ferroelectrics of interest are already studied and considered for random access memories. Shifting of curie temperature is related to the strontium content in the BST ceramic [1]. Samples were prepared for x = 0.10, 0.15, 0.20 and 0.22. Solid state reaction method is used for preparing different compositions. Pellets with diameter 8 mm using dia piston were prepared. For these pellets, the dielectric properties were observed between room temperature and 126 o C, for different Sr content. X-Ray powder diffraction study shows the structural and crystal symmetry for different strontium content. Transition of curie point, towards room temperature is observed with increasing strontium content. Low and fairly constant dielectric loss, near room temperature is observed, which is suitable for dynamic random access memory (DRAM) cell. Furthermore, composition dependent dielectric conductivity plot shows different region of conduction process. Study shows BST ceramics, with increasing Sr content are very important candidate for a wide range of applications. Keywords: Barium Strontium Titanate, Electrical properties, Ceramics, Ferroelectric transitions, Solid state reaction. I. INTRODUCTION erroelectric materials of BaTiO 3 -based solid solutions with perovskite structure are primarily utilized in the electronic industry [2, 3]. There are several other important ferroelectric materials which were studied such as PbTiO 3 , SrBiTaO 3 , Pb(MgNb)O 3 and BaTiO 3, which is the origin of (BaSr)TiO 3 [4]. BST is a material with high degree of crystallinity, high dielectric constant, high charge storage capacity and low leakage current at curie’s temperature [5, 6]. In particular, BST ceramics are considered most suitable dielectric material for high density capacitors in DRAMs [7, 8]. Most of the microwave application requires material with low dielectric loss and dependence on temperature, of the dielectric constant. It is already reported that BST material exhibit high dielectric loss in microwave range. For the BaO- SrO-TiO 2 system, a 50% medium line in the phase diagram shows the unlimited solubility between BaTiO 3 and SrTiO 3 [1]. Therefore different Sr content BST materials are required to be investigated. The transition temperature of BaTiO 3 is 120 o C [9]. It is reported that the doping of strontium in BaTiO 3 ceramic has a great effect on the transition temperature [1]. When strontium atoms were introduced to A site in perovskite barium titanate matrix to replace barium atoms, the phase transition temperature of paraelectric to ferroelectric decreases. The curie temperature of BST can be varied for different strontium contents, that changes, the phase of the BST ceramics [10]. It is observed that, size of Ba and Sr also have major impact on the electrical properties of BST ceramic [1, 11]. So many methods have been focused on the processing methods as precipitation [12], sol-gel [13, 14], hydro thermal [15] and conventional methods. II. EXPERIMENTAL Barium Carbonate (BaCO 3 ) and Strontium Carbonate (Sr 2 CO 3 ) were taken in the molar ratio 1-x : x, milled with Titanium Dioxide (TiO 2 ), where Sr content is varied for x= 0.1 to x=0.22. Conventional solid state reaction method was used to prepare different compositions. Reagent grade barium carbonate, strontium carbonate and Titanate of high purity 99.0% were used as starting materials. The raw material was dried at 150 o C for one hour, weighed in stoichiometric proportions, manual grinding in acetone for 2 hr (wet), 4 hr (dry), and then calcinated at 1000 o C for 4 hr. After calcinations the obtained powder was taken for XRD analysis. XRD analysis was obtained for intensity versus angle (2θ, in the range between 20 to 70). Pellets were prepared at a pressure of 2GPascal, with diameter 8 mm dia piston. These pellets were sintered at temperature 1250 o C for 4 hrs. Sintered pellets were crushed into powder and again the crystalline orientation was measured by X-ray diffraction (XRD), on a X-Pert PANalytical diffractometer using a fixed divergence1/2 o slit, a Cu W/Si mirror , a solar slit and a 10 mm mask as incident optics and a parallel plate collimator, a solar slit and a proportional detector as diffracted beam optics. The result from the machine indicates that only pure perovskite structure exists for all BST ceramics with different Sr content. Sintered pellet was coated both side, with silver paste. The coated pellet was dried for 2 hr at room temperature (25 o C). A computer controlled system, including RCL meter (make: Fluke, model: PM6306) was used to measure temperature and frequency dependence of dielectric properties. Both low frequency (1 KHz) and high frequency F