Functional piezocrystal characterisation under varying conditions

Liao, X., Qiu, Z., Jiang, T., Sadiq, M., Huang, Z., Demore, C. and Cochran, S. (2015) Functional piezocrystal characterisation under varying conditions. Materials, 8(12), pp. 8304-8326. (doi: 10.3390/ma8125456)

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Abstract

Piezocrystals, especially the relaxor-based ferroelectric crystals, have been subject to intense investigation and development within the past three decades, motivated by the performance advantages offered by their ultrahigh piezoelectric coefficients and higher electromechanical coupling coefficients than piezoceramics. Structural anisotropy of piezocrystals also provides opportunities for devices to operate in novel vibration modes, such as the d36 face shear mode, with domain engineering and special crystal cuts. These piezocrystal characteristics contribute to their potential usage in a wide range of low- and high-power ultrasound applications. In such applications, conventional piezoelectric materials are presently subject to varying mechanical stress/pressure, temperature and electric field conditions. However, as observed previously, piezocrystal properties are significantly affected by a single such condition or a combination of conditions. Laboratory characterisation of the piezocrystal properties under these conditions is therefore essential to fully understand these materials and to allow electroacoustic transducer design in realistic scenarios. This will help to establish the extent to which these high performance piezocrystals can replace conventional piezoceramics in demanding applications. However, such characterisation requires specific experimental arrangements, examples of which are reported here, along with relevant results. The measurements include high frequency-resolution impedance spectroscopy with the piezocrystal material under mechanical stress 0–60 MPa, temperature 20–200 °C, high electric AC drive and DC bias. A laser Doppler vibrometer and infrared thermal camera are also integrated into the measurement system for vibration mode shape scanning and thermal conditioning with high AC drive. Three generations of piezocrystal have been tested: (I) binary, PMN-PT; (II) ternary, PIN-PMN-PT; and (III) doped ternary, Mn:PIN-PMN-PT. Utilising resonant mode analysis, variations in elastic, dielectric and piezoelectric constants and coupling coefficients have been analysed, and tests with thermal conditioning have been carried out to assess the stability of the piezocrystals under high power conditions.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Cochran, Professor Sandy and Liao, Mr Xiaochun and Demore, Dr Christine
Authors: Liao, X., Qiu, Z., Jiang, T., Sadiq, M., Huang, Z., Demore, C., and Cochran, S.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Materials
Publisher:MDPI
ISSN:1996-1944
ISSN (Online):1996-1944
Copyright Holders:Copyright © 2015 by the Authors
First Published:First published in Materials 8(12):8304-8326
Publisher Policy:Reproduced in accordance with the publisher policy

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
610721Ultrasonic Needles based on Mn-doped Ternary PiezocrystalsMargaret LucasEngineering & Physical Sciences Research Council (EPSRC)EP/K020013/1ENG - ENGINEERING SYSTEMS POWER & ENERGY