Towards an understanding of the anomalous electromechanical behaviour of langasite and related compounds at high temperatures

Schreuer, J.; Thybaut, C.; Prestat, Michel; Stade, J.; Haussühl, Eiken

doi:10.1109/ultsym.2003.1293387

Cited by 24 publications

(13 citation statements)

References 12 publications

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“…37). The extend of the peak depends on the thermal history of the sample as also reported in [66,98]. Further, the observation is in general agreement with results presented in [99].…”

Section: Activation Energies Of Loss and Conductivitysupporting

confidence: 91%

High-temperature piezoelectric crystals and devices

Fritze

2011

J Electroceram

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Conventional piezoelectric materials such as quartz are widely used as high precision transducers and sensors based on bulk acoustic waves. However, their operation temperature is limited by the intrinsic materials properties to about 500 • C. High-temperature applications are feasible by applying materials that retain their piezoelectric properties up to higher temperatures. Here, langasite (La 3 Ga 5 SiO 14 ) and compounds of the langasite family are the most promising candidates, since they are shown to exhibit bulk acoustic waves up to at least 1400 • C. The mass sensitivity of langasite resonators at elevated temperatures is about as high as that of quartz at room temperature. Factors limiting potential use of those crystals include excessive conductive and viscous losses, deviations from stoichiometry and chemical instability. Therefore, the objective of this work is to identify the related microscopic mechanisms, to correlate electromechanical properties and defect chemistry and to improve the stability of the materials by e.g. appropriate dopants.Further application examples such as resonant gas sensors are given to demonstrate the capabilities of hightemperature stable piezoelectric materials. The electromechanical properties of langasite are determined and described by a one-dimensional physical model. Key properties relevant for stable operation of resonators are found to be shear modulus, density, electrical conductivity and effective viscosity. In order to quantify their impact on frequency and damping, a general-H. Fritze (B)

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“…37). The extend of the peak depends on the thermal history of the sample as also reported in [66,98]. Further, the observation is in general agreement with results presented in [99].…”

Section: Activation Energies Of Loss and Conductivitysupporting

confidence: 91%

High-temperature piezoelectric crystals and devices

Fritze

2011

J Electroceram

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“…In order to extract these values, the Igor Pro software was used for fitting each resonance peak by means of asymmetric Lorentzian function [74,75], which implements the condition of fitting both sides of the peak with two different profiles (Eqs. 18 and 19).…”

Section: Temperature-dependent Elastic Propertiesmentioning

confidence: 99%

Elastic and anelastic relaxations accompanying relaxor ferroelectric behaviour of Ba6GaNb9O30 tetragonal tungsten bronze from resonant ultrasound spectroscopy

Rotaru

Schiemer

Carpenter

2016

J Therm Anal Calorim

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Tetragonal tungsten bronze (TTB) structures offer some promise as lead-free ferroelectrics and have an advantage of great flexibility in terms of accessible composition ranges due to the number of crystallographic sites available for chemical substitution. The ferroic properties of interest are coupled with strain, which will be important in the context of stability, switching dynamics and thin film properties. Coupling of strain with the ferroelectric order parameter gives rise to changes in elastic properties, and these have been investigated for a ceramic sample of Ba 6 GaNb 9 O 30 (BGNO) by resonant ultrasound spectroscopy. Room temperature values of the shear and bulk moduli for BGNO are rather higher than for TTBs with related composition which are orthorhombic at room temperature, consistent with suppression of the ferroelectric transition. Instead, a broad, rounded minimum in the shear modulus measured at *1 MHz is accompanied by a broad rounded maximum in acoustic loss near 115 K and signifies relaxor freezing behaviour. Elastic softening with falling temperature from room temperature, ahead of the freezing interval, is attributed to the development of dynamical polar nanoregions (PNRs), whilst the nonlinear stiffening below *115 K is consistent with a spectrum of relaxation times for freezing of the PNR microstructure.

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“…Peak positions were again used to calculate values of G and K, in this case following the methodology described by Schreuer (2002), Schreuer andThybaut (2005) and Schreuer et al (2006). Linewidths were determined using the asymmetric Lorentzian peak-fitting procedure of Schreuer et al (2003) and Schreuer and Thybaut (2005), in order to obtain values of Q. The effects of thermal expansion are expected to be small in comparison with changes in the intrinsic elastic constants with temperature and changes due to phase transitions.…”

Section: Rus Data Collection and Analysismentioning

confidence: 99%

Elastic and anelastic anomalies in (Ca,Sr)TiO3 perovskites: Analogue behaviour for silicate perovskites

Walsh

Taylor

Buckley

et al. 2008

Physics of the Earth and Planetary Interiors

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Page 1

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Towards an understanding of the anomalous electromechanical behaviour of langasite and related compounds at high temperatures

Cited by 24 publications

References 12 publications

High-temperature piezoelectric crystals and devices

High-temperature piezoelectric crystals and devices

Elastic and anelastic relaxations accompanying relaxor ferroelectric behaviour of Ba6GaNb9O30 tetragonal tungsten bronze from resonant ultrasound spectroscopy

Elastic and anelastic anomalies in (Ca,Sr)TiO3 perovskites: Analogue behaviour for silicate perovskites

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