Structural investigations on the (Ba,Sr)(Zr,Ti)O₃system

Abstract

Structural investigations of the compounds in the series Ba0.27Sr0.73ZryTi1-yO3 have been carried out. The crystal structure goes to lower symmetry with increasing Zr content and the tolerance factor decreases. The variation of Va/Vb is linear with the tolerance factor. The tilt system is a-a-c0 for compositions with y = 0.50 and 0.65. The tilt system is a-a-c+ for compositions with y = 0.80, 0.90 and 0.97 and for BSZT (Ba0.29Sr0.71Zr0.97Ti0.03O3) and BSZTTa (Ba0.29Sr0.71Zr0.95Ti0.04Ta0.01O3). The tilt angle with respect to the pseudocubic [100] and [001] directions increases with the Zr content. For compositions with y = 0, 0.25 and 0.40, the coordination of the A ion (Ba or Sr) is 12, whereas the A-ion coordination number is 11 for compounds with y = 0.50 and 0.65 and it is lower for compositions with y = 0.80, 0.90 and 0.97 and for the compounds BSZT and BSZTTa. The decrease in coordination number indicates that the compounds are becoming more and more covalent with increasing Zr content. A graph of |90°-pc| against the tolerance factor shows that |90°-pc| falls sharply at a tolerance factor corresponding to the compositions used in the fabrication of dielectric resonators. TCf values show that the sign of this parameter changes at a tolerance factor near 0.965 and has a minimum for compounds with orthorhombic Pbnm/Pnma structures.

Mechanical and dielectric behaviors of perovskite (Ba,Sr)TiO3 borosilicate glass ceramics

“…3, and it confirms the formation of major crystalline phase of BST along with secondary phase of BTS which is similar to XRD pattern of glass ceramic sample BST5K1L0.4S850 sintered for 6 h (Fig. 4) [23]. The crystallite size decreases with increasing the sintering time for the crystallization of the calcined glass samples.…”

Sol–Gel Processing and Characterizations of a Ba0.75Sr0.25Ti 0.95Zr0.05O3 Ceramic

“…This crystallization can be further confirmed by the XRD results. The diffraction pattern for the powder calcined at 600°C shows that the majority of the powder has crystallized into the BaSrTiZrO 3 perovskite structure . Peaks of Ba 0.75 Sr 0.25 Ti 0.95 Zr 0.05 O 3 were identified using the ICDD database (International Centre for Diffraction Data, Newton Square, PA).…”

Complex perovskite oxide nanocrystals: low-temperature synthesis and crystal structure

“…The synthesis of alkaline-earth perovskite oxide micro-and nanocrystals has been accomplished using a variety of methods that includes: solid state reaction, [6][7][8][9] molten salt, 10,11 sol-gel, 12,13 single-step combustion, 14,15 flame-spray pyrolysis, 16 thermal decomposition of a single-source precursor, 17 sol-precipitation, [18][19][20] reverse micelles, 21 polymeric precursor, 9 and solvothermal synthesis. [22][23][24][25][26][27] These synthetic approaches invariably rely on physical (heat, pressure) and/or chemical (salt, complexing agent, surfactant, mineralizer) agents to achieve a crystalline and phase-pure perovskite product.…”