High-temperature electromechanical loss in piezoelectric langasite and catangasite crystals

Suhak, Yuriy; Fritze, Holger; Сотников, А. В.; Schmidt, H.; Johnson, Ward L.

doi:10.1063/5.0058751

Cited by 8 publications

(2 citation statements)

References 57 publications

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“…The origin of piezoelectric stiffening is the polarization within the crystal due to the external electrical excitation voltage (Johannsmann and Heim, 2006). For 5 MHz CTGS resonators, k 2 is about 2 % between room temperature and 900 • C (Suhak et al, 2018(Suhak et al, , 2021. Furthermore, the coupling is impacted by the resonator geometry (IEEE, 1988).…”

Section: Modelling Of Tsm Resonatorsmentioning

confidence: 99%

Impact of electrode conductivity on mass sensitivity of piezoelectric resonators at high temperatures

Schlack

Wulfmeier

Fritze

2022

J. Sens. Sens. Syst.

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Abstract. High-temperature stable piezoelectric Ca3TaGa3Si2O14 and La3Ga5SiO14 resonators with keyhole-shaped Pt electrodes are coated with metal oxide films such as TiO2−δ and SnO2 that overlap the Pt electrodes. The resonators are exposed to reducing atmospheres in order to increase the electrical conductivity of the oxide film and then act as extended oxide electrodes. The resulting increase in the effective electrode radius causes an increase in the mass sensitivity of the resonators and, thereby, resonance frequency shifts. In other words, the effective mass of the Pt electrode becomes higher. An electrical circuit model is presented to describe the increase in the effective electrode radius of the resonator, which is used to calculate the related resonance frequency shift. Additionally, an electromechanical model is presented, which subdivides the resonator into two coupled oscillators. One is representing the resonator volume underneath the Pt electrode and the other underneath the oxide electrode at increased electrical conductivity. The model reflects how the oxide electrodes affect the resonance frequency. Furthermore, the impact of increasing oxide electrode conductivity on the resonance frequency is discussed with respect to the application of oxide electrodes and for gas sensing.

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Section: Modelling Of Tsm Resonatorsmentioning

confidence: 99%

Impact of electrode conductivity on mass sensitivity of piezoelectric resonators at high temperatures

Schlack

Wulfmeier

Fritze

2022

J. Sens. Sens. Syst.

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“…According to the occupation of cations, they can be divided into structural ordered- and disordered-type crystals; i.e., different cations randomly occupy the same lattice position in disordered crystals, whereas different cations occupy their respective positions in ordered crystals. The resistivity of the ordered crystals is generally higher compared to that of disordered crystals. − It was reported that the structural ordered Ca 3 TaGa 3 Si 2 O 14 (CTGS, ∼1.0 × 10 11 Ω·cm) crystal exhibits the highest resistivity among the langasite-type crystals, 2 orders of magnitude higher than that of the disordered La 3 Ga 5 SiO 14 (LGS, ∼8.0 × 10 8 Ω·cm) crystal at 300 °C . The relatively low resistivity of LGS is mainly attributed to the high conductivity caused by oxygen vacancies (V O ).…”

Section: Introductionmentioning

confidence: 99%

Intrinsic Defects and the Inducing Conduction Mechanism of Langasite-Type High-Temperature Piezoelectric Crystals

Bai

Liu

Zhao

et al. 2023

ACS Appl. Mater. Interfaces

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Increasing the crystal resistivity is critically important for enhancing the signal-to-noise ratio and improving the sensing capability of high-temperature piezoelectric sensors based on langasite-type crystals. The resistivity of structural ordered langasite-type crystals is much higher compared to that of the disordered crystals. Here, we selected structural ordered Ca 3 TaGa 3 Si 2 O 14 (CTGS) and disordered La 3 Ga 5 SiO 14 (LGS) as representatives to investigate the microscopic conduction mechanism and further reveal the origin of the different resistivities of the ordered and disordered langasite-type crystals at elevated temperatures. By combining first-principles calculations and experimental investigations, we found that the different conductivity behaviors of the ordered and disordered crystals originate from different types of point defects formed in the crystal and their different contributions to the conductivity. For the disordered LGS crystal, the oxygen vacancies are apt to be formed at high temperatures, promoting the transition of valence electrons and yielding high conductivity. For the ordered CTGS crystal, the dominant Ta Ga antisite defects can introduce an electron−hole recombination center in the electronic band gap, significantly shortening the carrier lifetime and thus reducing the conductivity. This provides effective guidance to improve the resistivity performance of langasite-type crystals at high temperatures by optimizing the experimental conditions, such as oxygen atmosphere treatment, antisite defect modification, etc.

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Characterization of Elastic Constants of Langatate Single Crystals with 32 Symmetry Using Ultrasonic Pulse‐Echo Technique

Chen,

Qin,

et al. 2024

Cryst. Res. Technol.

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In this study, the propagation of plane waves in the lanthanum gallium tantalate (langatate, LGT) single crystals is investigated. Moreover, the flight time of different waves in the LGT rectangular parallelepiped sample is measured using the ultrasonic pulse‐echo (UPE) technique, and the elastic constants of the LGT sample are determined. The experimental results clearly show echoes corresponding to the longitudinal and transverse waves along the x‐axis. The waves along the z‐axis have a similar property. However, the waves along the y‐axis are more complex than those along the x‐ and z‐axes. The echoes corresponding to the quasi‐longitudinal waves along the y‐axis are clear, but those corresponding to the transverse and quasi‐transverse waves along the y‐axis are not. The elastic constant can be accurately determined if the wave echoes corresponding to this constant propagate without distinct distortion and are clear; otherwise, it may be impossible to accurately determine the constant using UPE. All elastic constants except of the LGT single crystals can be determined using UPE from one sample. This study uses UPE to provide a reference for the characterization of elastic constants of piezoelectric crystals with 32 symmetry from one sample.

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High-temperature electromechanical loss in piezoelectric langasite and catangasite crystals

Cited by 8 publications

References 57 publications

Impact of electrode conductivity on mass sensitivity of piezoelectric resonators at high temperatures

Impact of electrode conductivity on mass sensitivity of piezoelectric resonators at high temperatures

Intrinsic Defects and the Inducing Conduction Mechanism of Langasite-Type High-Temperature Piezoelectric Crystals

Characterization of Elastic Constants of Langatate Single Crystals with 32 Symmetry Using Ultrasonic Pulse‐Echo Technique

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