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Flux Growth and characterization of lead-free Sodium Bismuth Titanate -Barium Titanate (NBBT) at composition near the morphotropic phase boundary

Aravinth Karuppanan ,  Anandha Babu Govindan ,  Ramasamy Perumalsamy 

Centre for Crystal Growth,SSN College of Engineering,Kalavakkam,Chennai, Chennai 603110, India

Abstract

In recent years, growing attention has been given to the research for improving piezoelectric properties of lead-free piezoelectric materials, which are viewed as possible substitutes for lead-based piezoelectric materials from the viewpoint of environmental protection. Among these NBT-based solid solutions, Na1/2Bi1/2TiO3–BaTiO3 (NBBT) system is most attractive due to their excellent piezoelectric properties, which exists as morphotropic phase boundary (MPB) between the rhombohedral phase (NBT) and the tetragonal phase (BT). The improved electromechanical properties can be generally achieved in single crystals based on engineering domain configuration. So it is expected that the superior piezoelectric properties could be achieved in NBBT94/6 single crystal. 0.94NBT-0.06BT single crystal with reasonable size has been successfully grown by flux growth method. Single crystal X-ray diffraction (SXRD) was used to confirm the crystal system of the grown NBBT94/6 crystal. The Energy Dispersive X-Ray analysis method was used to measure the concentrations of Ba, Bi, Ti and Na elements in the as-grown crystal. The temperature dependence of dielectric constant for various frequencies (100 Hz–2 MHz) has been determined. Two dielectric anomalies are observed at 159oC and 310oC, corresponding to the depolarization temperature (Td) and Curie temperature (Tm). The dielectric data fitted with Curie-Weiss law shows that the gamma value of the as-grown crystal is 1.46, which also confirms the better relaxor behavior.

 
 

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Related papers

Presentation: Oral at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, Topical Session 6, by Aravinth Karuppanan
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17

Submitted: 2013-04-15 11:35
Revised:   2013-04-15 11:53