Campus Units

Materials Science and Engineering

Document Type

Article

Publication Version

Published Version

Publication Date

7-18-2016

Journal or Book Title

Journal of Applied Physics

Volume

120

Issue

034102

First Page

1

Last Page

7

DOI

10.1063/1.4958853

Abstract

Non-textured polycrystalline [Bi1/2 (Na 0.8K0.2)1/2](Ti1− x Ta x)O3 ceramics are fabricated and their microstructures and electrical properties are characterized. Transmission electron microscopy reveals the coexistence of the rhombohedral R3c and tetragonal P4bm phases in the form of nanometer-sized domains in [Bi1/2 (Na 0.8K0.2)1/2]TiO3 with low Ta concentration. When the composition is x = 0.015, the electrostrain is found to be highly asymmetric under bipolar fields of ±50 kV/cm. A very large value of 0.62% is observed in this ceramic, corresponding to a large-signal piezoelectric coefficient d 33* of 1240 pm/V (1120 pm/V under unipolar loading). These values are greater than most previously reported lead-free polycrystalline ceramics and can even be compared with some lead-free piezoelectric single crystals. Additionally, this ceramic displays low cycling degradation; its electrostrain remains above 0.55% even after undergoing 10 000 cycles of ±50 kV/cm bipolar fields at 2 Hz. Therefore, Ta-doped [Bi1/2(Na 0.8K0.2)1/2]TiO3 ceramics show great potential for large displacement devices.

Comments

The following article appeared in Journal of Applied Physics 120 (2016); and may be found at doi:10.1063/1.4958853.

Copyright Owner

The Authors

File Format

application/pdf

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