Effect of Composition on the Growth of Single Crystals of (1-x)(Na1/2Bi1/2)TiO3-xSrTiO3 by Solid State Crystal Growth.

Le Le,Moon Moon,Fisher Fisher

doi:10.3390/ma12152357

Le Le, Moon Moon + Show 1 more

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https://doi.org/10.3390/ma12152357

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Abstract

The (1−x)(Na1/2Bi1/2)TiO3-xSrTiO3 (NBT-100xST) system is a possible lead-free candidate for actuator applications because of its excellent strain vs. electric field behaviour. Use of single crystals instead of polycrystalline ceramics may lead to further improvement in piezoelectric properties but work on single crystal growth in this system is limited. In particular, the effect of composition on single crystal growth has yet to be studied. In this work, single crystals of (NBT-100xST) with x = 0.00, 0.05, 0.10 and 0.20 were grown using the method of Solid State Crystal Growth. [001]-oriented SrTiO3 single crystal seeds were embedded in (NBT-100xST) ceramic powder, which was then pressed to form pellets and sintered at 1200 °C for 5 min–50 h. Single crystal growth rate, matrix grain growth rate and sample microstructure were examined using scanning and transmission electron microscopy. The results indicate that the highest single crystal growth rate was obtained at x = 0.20. The mixed control theory of grain growth is used to explain the single crystal and matrix grain growth behaviour.

Highlights

Td, the rhombohedral-tetragonal phase transition temperature TR-T and Tm can be altered by adding dopants or by forming solid solutions with other perovskite compounds [8,9,10,11]. (Na1/2 Bi1/2 )TiO3 exhibits strong ferroelectricity with remnant polarization of Pr = 38 μC/cm2, but the high coercive field of 7 kV/mm makes the poling process difficult [12]
Secondary phases are not visible in the patterns of the patterns were indexed with pdf card # 98-015-4342 in the ICDD database
Both single crystal and matrix grain growth in the (1−x) (Na1/2 Bi1/2 )TiO3 -xSrTiO3 system depend on the structure of the solid/liquid interfaces or grain boundaries, which can be disordered or ordered on the atomic level [24,32,33,34,35,36]

Summary

Introduction

The (1−x)(Na1/2 Bi1/2 )TiO3 -xSrTiO3 (NBT-100xST) system is a possible lead-free candidate for actuator applications because of its excellent strain vs electric field behaviour. Single crystals of (NBT-100xST) with x = 0.00, 0.05, 0.10 and 0.20 were grown using the method of Solid State Crystal Growth. [001]-oriented SrTiO3 single crystal seeds were embedded in (NBT-100xST) ceramic powder, which was pressed to form pellets and sintered at 1200 ◦ C for 5 min–50 h. (Na1/2 Bi1/2 )TiO3 (NBT) is a perovskite material with rhombohedral symmetry at temperatures lower than 255 ◦ C, tetragonal symmetry at temperatures between 255–540 ◦ C, and cubic symmetry at temperatures above 540 ◦ C [3,4,5,6,7].

Results

Discussion

Conclusion