ANALYSIS OF COUPLED FAST-SHEAR AND EXTENSIONAL VIBRATIONS OF A LITAO3 CRYSTAL PLATE WITH A FERROELECTRIC INVERSION LAYER
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- 英文论文题名：ANALYSIS OF COUPLED FAST-SHEAR AND EXTENSIONAL VIBRATIONS OF A LITAO3 CRYSTAL PLATE WITH A FERROELECTRIC INVERSION LAYER
- 论文作者：Ting-feng MA ; Jie-yu PEI ; Qiong ZHANG ; Ji WANG ; Jian-ke DU ; Bin HUANG ; Rong-xing WU
- 英文论文作者：Ting-feng MA ; Jie-yu PEI ; Qiong ZHANG ; Ji WANG ; Jian-ke DU ; Bin HUANG ; Rong-xing WU ; Piezoelectric Device Laboratory ; School of Mechanical Engineering and Mechanics ; Ningbo University
- 年：2016
- 作者机构：Piezoelectric Device Laboratory, School of Mechanical Engineering and Mechanics,Ningbo University;
- 英文论文关键词：Piezoelectric crystal plate ; Resonator ; Inversion layer ; Fast-shear overtone mode ; LiTaO_3
- 会议召开时间：2016-10-21
- 会议录名称：2016年全国压电和声波理论及器件应用研讨会论文摘要集
- 英文会议录名称：Abstract Book of 2016 Symposium on Piezoelectricity, Acoustic Waves and Device Applications
- 语种：英文
- 分类号：TN384
- 学会代码：AGLU
- 会议名称：2016年全国压电和声波理论及器件应用研讨会
- 会议地点：中国陕西西安
- 主办单位：中国力学学会、中国声学学会、IEEE UFFC分会
- 学会名称：中国力学学会
- 页数：2
- 文件大小：13k
- 原文格式：D
- 会议级别：全国
摘要
Background, Motivation and Objective Previous studies showed that a ferroelectric domain inversion arose when LiNbO_3 or LiTaO_3 plates were heat-treated at temperatures higher than the curie point of the crystal. In the heating process, the ferroelectric inversion layer grows gradually, and the domain boundary ultimately stops growing near the middle plane of the plate after a sufficiently long heat treatment is performed. For a ferroelectric inversion layer, the piezoelectric constants are opposite in sign to those of a regular layer. The inversion layer is less involved with spurious modes in resonators working on thickness-shear modes. This implies better frequency stability for a resonator with an inversion layer. For LiTaO_3 crystals, fast-shear modes depend on temperature to a lower extent than slow-shear modes, with this characteristic, frequency stability of bulk acoustic wave sensors is significantly improved. Thus, LiTaO_3 crystal resonators with an inversion layer operating on the fast-shear mode have a good application prospect on high-stability piezoelectric sensors. Analytical models on inversion layer devices are scarce. Zhou et al. present the analytical model of inversion layer devices operating with the thickness-extension mode. For LiTaO_3 resonators working on fast-shear mode with a ferroelectric inversion layer, basic vibration characteristics have not been systematically studied, and the effects of parameters of devices on resonance characteristics remain unclear, which are the basis of the design of the new inversion layer resonator operating on the fast-shear mode. In this study, we perform a systematic analysis of coupled fast-shear and extension vibrations in LiTaO_3 inversion layer resonators, and reveal the effects of parameters of devices on the resonance characteristics. Statement of Contribution/Methods The linear theory of piezoelectricity is used to analyze coupled fast-shear and extensional vibrations of a LiTaO_3 crystal plate with a ferroelectric inversion layer. Capacitance ratio-frequency characteristics of the device are calculated and the displacement distributions near resonances are examined. The influences of the relative thickness of the inversion layer on the resonance modes are revealed.Results Results show that the capacitance ratio assumes maxima at two resonances, which are identified to be the second overtone modes of fast-shear and extension, respectively. Besides, it is found that the thickness of the inversion layer has obvious influences on the capacitance ratio of fast-shear and extensional modes. This condition may provide a simple method to adjust capacitance ratios of piezoelectric resonators. Discussion and Conclusions Capacitance ratio determines the influence of changes in impedance of the oscillating circuit on changes in resonance frequency. The capacitance ratio receives considerable attention because the frequency of the resonator usually need to be changed through adjusting the impedance of the oscillating circuit. A large change in frequency caused by a change in impedance of the oscillating circuit can be obtained with a large capacitance ratio. If the length/thickness ratio of a crystal plate, which determines mode coupling, is fixed, the capacitance ratio is usually difficult to increase for a resonator without an inversion layer. Nevertheless, for a resonator with an inversion layer, the relative thickness of an inversion layer can be adjusted easily by controlling heat treatment time of crystal plates. Therefore, capacitance ratios of piezoelectric resonators can be adjusted by changing the relative thickness of an inversion layer. This condition may provide a new and simple method to adjust capacitance ratios of piezoelectric resonators.
Background, Motivation and Objective Previous studies showed that a ferroelectric domain inversion arose when LiNbO_3 or LiTaO_3 plates were heat-treated at temperatures higher than the curie point of the crystal. In the heating process, the ferroelectric inversion layer grows gradually, and the domain boundary ultimately stops growing near the middle plane of the plate after a sufficiently long heat treatment is performed. For a ferroelectric inversion layer, the piezoelectric constants are opposite in sign to those of a regular layer. The inversion layer is less involved with spurious modes in resonators working on thickness-shear modes. This implies better frequency stability for a resonator with an inversion layer. For LiTaO_3 crystals, fast-shear modes depend on temperature to a lower extent than slow-shear modes, with this characteristic, frequency stability of bulk acoustic wave sensors is significantly improved. Thus, LiTaO_3 crystal resonators with an inversion layer operating on the fast-shear mode have a good application prospect on high-stability piezoelectric sensors. Analytical models on inversion layer devices are scarce. Zhou et al. present the analytical model of inversion layer devices operating with the thickness-extension mode. For LiTaO_3 resonators working on fast-shear mode with a ferroelectric inversion layer, basic vibration characteristics have not been systematically studied, and the effects of parameters of devices on resonance characteristics remain unclear, which are the basis of the design of the new inversion layer resonator operating on the fast-shear mode. In this study, we perform a systematic analysis of coupled fast-shear and extension vibrations in LiTaO_3 inversion layer resonators, and reveal the effects of parameters of devices on the resonance characteristics. Statement of Contribution/Methods The linear theory of piezoelectricity is used to analyze coupled fast-shear and extensional vibrations of a LiTaO_3 crystal plate with a ferroelectric inversion layer. Capacitance ratio-frequency characteristics of the device are calculated and the displacement distributions near resonances are examined. The influences of the relative thickness of the inversion layer on the resonance modes are revealed.Results Results show that the capacitance ratio assumes maxima at two resonances, which are identified to be the second overtone modes of fast-shear and extension, respectively. Besides, it is found that the thickness of the inversion layer has obvious influences on the capacitance ratio of fast-shear and extensional modes. This condition may provide a simple method to adjust capacitance ratios of piezoelectric resonators. Discussion and Conclusions Capacitance ratio determines the influence of changes in impedance of the oscillating circuit on changes in resonance frequency. The capacitance ratio receives considerable attention because the frequency of the resonator usually need to be changed through adjusting the impedance of the oscillating circuit. A large change in frequency caused by a change in impedance of the oscillating circuit can be obtained with a large capacitance ratio. If the length/thickness ratio of a crystal plate, which determines mode coupling, is fixed, the capacitance ratio is usually difficult to increase for a resonator without an inversion layer. Nevertheless, for a resonator with an inversion layer, the relative thickness of an inversion layer can be adjusted easily by controlling heat treatment time of crystal plates. Therefore, capacitance ratios of piezoelectric resonators can be adjusted by changing the relative thickness of an inversion layer. This condition may provide a new and simple method to adjust capacitance ratios of piezoelectric resonators.
Background, Motivation and Objective Previous studies showed that a ferroelectric domain inversion arose when LiNbO_3 or LiTaO_3 plates were heat-treated at temperatures higher than the curie point of the crystal. In the heating process, the ferroelectric inversion layer grows gradually, and the domain boundary ultimately stops growing near the middle plane of the plate after a sufficiently long heat treatment is performed. For a ferroelectric inversion layer, the piezoelectric constants are opposite in sign to those of a regular layer. The inversion layer is less involved with spurious modes in resonators working on thickness-shear modes. This implies better frequency stability for a resonator with an inversion layer. For LiTaO_3 crystals, fast-shear modes depend on temperature to a lower extent than slow-shear modes, with this characteristic, frequency stability of bulk acoustic wave sensors is significantly improved. Thus, LiTaO_3 crystal resonators with an inversion layer operating on the fast-shear mode have a good application prospect on high-stability piezoelectric sensors. Analytical models on inversion layer devices are scarce. Zhou et al. present the analytical model of inversion layer devices operating with the thickness-extension mode. For LiTaO_3 resonators working on fast-shear mode with a ferroelectric inversion layer, basic vibration characteristics have not been systematically studied, and the effects of parameters of devices on resonance characteristics remain unclear, which are the basis of the design of the new inversion layer resonator operating on the fast-shear mode. In this study, we perform a systematic analysis of coupled fast-shear and extension vibrations in LiTaO_3 inversion layer resonators, and reveal the effects of parameters of devices on the resonance characteristics. Statement of Contribution/Methods The linear theory of piezoelectricity is used to analyze coupled fast-shear and extensional vibrations of a LiTaO_3 crystal plate with a ferroelectric inversion layer. Capacitance ratio-frequency characteristics of the device are calculated and the displacement distributions near resonances are examined. The influences of the relative thickness of the inversion layer on the resonance modes are revealed.Results Results show that the capacitance ratio assumes maxima at two resonances, which are identified to be the second overtone modes of fast-shear and extension, respectively. Besides, it is found that the thickness of the inversion layer has obvious influences on the capacitance ratio of fast-shear and extensional modes. This condition may provide a simple method to adjust capacitance ratios of piezoelectric resonators. Discussion and Conclusions Capacitance ratio determines the influence of changes in impedance of the oscillating circuit on changes in resonance frequency. The capacitance ratio receives considerable attention because the frequency of the resonator usually need to be changed through adjusting the impedance of the oscillating circuit. A large change in frequency caused by a change in impedance of the oscillating circuit can be obtained with a large capacitance ratio. If the length/thickness ratio of a crystal plate, which determines mode coupling, is fixed, the capacitance ratio is usually difficult to increase for a resonator without an inversion layer. Nevertheless, for a resonator with an inversion layer, the relative thickness of an inversion layer can be adjusted easily by controlling heat treatment time of crystal plates. Therefore, capacitance ratios of piezoelectric resonators can be adjusted by changing the relative thickness of an inversion layer. This condition may provide a new and simple method to adjust capacitance ratios of piezoelectric resonators.
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