Contributions to anelasticity in langasite and langatate

Johnson, Ward L.; Kim, Sudook A.; Uda, Satoshi; Rivenbark, Christine F.

doi:10.1063/1.3672443

Cited by 19 publications

(25 citation statements)

References 51 publications

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“…In order to investigate atomic transport mechanisms in CTGS, oxygen selfdiffusion is studied, because O is expected to be the most mobile atomic species in the crystal lattice [11]. These experiments were performed using the stable tracer isotope 18 O by annealing the samples in an 18 O 2 enriched atmosphere (90 % 18 O 2 , 200 mbar). Subsequently the 18 O depth profiles were analysed by secondary ion mass spectrometry (SIMS) (Hiden Analytical).…”

Section: Experimental Methodsmentioning

confidence: 99%

“…These experiments were performed using the stable tracer isotope 18 O by annealing the samples in an 18 O 2 enriched atmosphere (90 % 18 O 2 , 200 mbar). Subsequently the 18 O depth profiles were analysed by secondary ion mass spectrometry (SIMS) (Hiden Analytical). Prior to each diffusion run, each sample was pre-annealed in air to equilibrate it.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…To analyse oxygen self-diffusion, the secondary ion intensities I of 16 O and 18 O were recorded by SIMS as a function of sputtering time. Since these O isotopes are chemically identical, the intensity of the signal was converted to the 18 Figure 2. The fitting procedure is described in detail in [11].…”

Section: Atomic Transportmentioning

confidence: 99%

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Transport and Electromechanical Properties of Ca3TaGa3Si2O14 Piezoelectric Crystals at Extreme Temperatures

et al. 2019

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Transport mechanisms in structurally ordered piezoelectric Ca3TaGa3Si2O14 (CTGS) single crystals are studied in the temperature range of 1000-1300 °C by application of the isotope 18O as a tracer and subsequent analysis of diffusion profiles of this isotope using secondary ion mass spectrometry (SIMS). Determined oxygen self-diffusion coefficients enable calculation of oxygen ion contribution to the total conductivity, which is shown to be small. Since very low contributions of the cations have to be expected, the total conductivity must be dominated by electron transport. Ion and electron conductivities are governed by different mechanisms with activation energies (1.9±0.1) eV and (1.2±0.07) eV, respectively. Further, the electromechanical losses are studied as a function of temperature by means of impedance spectroscopy on samples with electrodes and a contactless tone-burst excitation technique. At temperatures above 650 °C the conductivity-related losses are dominant. Finally, the operation of CTGS resonators is demonstrated at cryogenic temperatures and materials piezoelectric strain constants are determined from 4.2 K to room temperature.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Experimental Methodsmentioning

confidence: 99%

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Transport and Electromechanical Properties of Ca3TaGa3Si2O14 Piezoelectric Crystals at Extreme Temperatures

et al. 2019

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“…For LGT, a full set of high temperature material constant have been recently reported [1], [15], thus enabling the design and investigation of high temperature AW devices [16], [17], [18]. In reference [19], anelastic properties of LGS and LGT have been studied for high temperature operation, targeting frequency control and mass deposition devices. Langasite crystals and devices have been exposed to abrupt shocks in temperature and pressure, and to turbine engine vibration environments without compromising the material integrity [20] [21].…”

Section: A Piezoelectric Crystals and Films For Harsh Environmentsmentioning

confidence: 99%

Wireless sensing in hostile environments

Cunha

2013

2013 IEEE International Ultrasonics Symposium (IUS)

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Microwave acoustic devices have long been shown to provide sensitive platforms for physical and gas sensors. Piezoelectric substrates introduced over the past two decades, such as the langasite (LGS) family of crystals, gallium orthophosphate, and aluminum nitride have enabled the exploration of microwave acoustics sensing at temperatures above 500°C. However the ability of the substrate to withstand high temperatures is only one of the requirements for sensor operation in harsh environments. Other prerequisites are: the development of stable high-temperature device electrodes; appropriate packaging; and resilience of the entire system to thermal shock and thermal cycling. In this paper, the wireless operation of microwave acoustic wave sensors in harsh environments is reviewed, and recent achievements are highlighted. Particular focus is given to surface acoustic wave (SAW) sensor technology because it has the advantage of being wireless, battery-free, and allows interrogation of arrays of multiple devices. During the last decade, wireless hostile environment microwave acoustic sensors that can detect gases and monitor temperature and pressure have transitioned from laboratory proof-of-concept to commercial devices and systems. Recent accomplishments in thin film technology and packaging are extending the technology to even higher temperatures, beyond 1000°C. These technological advances are enabling wireless microwave acoustic sensor applications in hostile environments including power plants, turbine engines, oil/gas refineries, and high temperature industrial processing.

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“…BAW LGT resonators have already demonstrated their efficiency as master resonators in very stable oscillators [11]. Since LGT-based devices exhibit similar low phase noise and high Q regimes as quartz devices, they can also be classified as a low-loss material [12]. Nevertheless, such applications require careful selection of the material in terms of crystal quality.…”

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confidence: 99%

Measurements of elastic properties of langatate at liquid helium temperatures for design of ultra low loss mechanical systems

Goryachev

Abbé

Dulmet

et al. 2014

Applied Physics Letters

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We present full characterisation of acoustic wave devices based on the fully synthetic crystalline material at the liquid helium temperature range required for the design of ultra low loss mechanical systems in many areas of research including frequency control and fundamental measurements. Temperature coefficients of the effective elastic tensor of Langatate (LGT) in Lagrangian representation are determined for the temperature range 3.8 − 15K. The Lagrangian formalism is mandatory in the analysed situation since the expansion coefficients of the LGT are still unknown at these temperatures. The measurement method involves a set of high-quality resonators of various cut angles, and uses measurements of frequency-temperature relations to extract the temperature coefficients of the elastic tensor. In addition, power sensitivity of LGT resonators at cryogenic temperatures is determined and dominant loss mechanism is identified.Recently low temperature applications of piezoelectric Bulk Acoustic Wave (BAW) devices has drawn serious attention due to their extraordinary quality factors [1][2][3]. Such applications include but not limited to frequency control systems [4], quantum hybrid devices[2, 5, 6] and atomic force spectroscopy. It is demonstrated [7,8] that in most of these applications, and in frequency control in particular [9], thermal response of such devices is critical and requires further improvement. For this purpose, thermal coefficient of the utilised material have to be identified at the liquid helium temperature range.Although langasite-type materials were initially developed as laser crystals, some of their properties make them very good candidates for frequency control applications. Like other compounds of this crystal family, Lanthanum gallium tantalite (La 3 Ga 5.5 Ta 0.5 O 14 ) or Langatate (LGT) belongs to the same trigonal crystal class 32 as quartz, and as a consequence exhibits similar properties. First, it is piezoelectric with an electromechanical coupling coefficient two to three times greater than that of quartz. These properties make Langatate ideal for variety of frequency-control applications including BAW and surface acoustic wave (SAW) resonators and filters [10]. BAW LGT resonators have already demonstrated their efficiency as master resonators in very stable oscillators [11]. Since LGT-based devices exhibit similar low phase noise and high Q regimes as quartz devices, they can also be classified as a low-loss material [12]. Nevertheless, such applications require careful selection of the material in terms of crystal quality. It should also be pointed out that LGT crystal can be made according to a purely synthetic process of growth whereas quartz crystal cannot be reproduce infinitely from synthetic seeds. Indeed, the crystalline quartz quality de-

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Contributions to anelasticity in langasite and langatate

Cited by 19 publications

References 51 publications

Transport and Electromechanical Properties of Ca3TaGa3Si2O14 Piezoelectric Crystals at Extreme Temperatures

Transport and Electromechanical Properties of Ca3TaGa3Si2O14 Piezoelectric Crystals at Extreme Temperatures

Wireless sensing in hostile environments

Measurements of elastic properties of langatate at liquid helium temperatures for design of ultra low loss mechanical systems

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