Transport and Electromechanical Properties of Ca3TaGa3Si2O14 Piezoelectric Crystals at Extreme Temperatures. (14th January 2019)

• Record Type: Journal Article
• Authors: Suhak, Yuriy; Johnson, Ward L.; Sotnikov, Andrei; Schmidt, Hagen; Fritze, Holger
• Is Part Of: MRS advances. Volume 4:Number 9(2019)
• Page Start: 515
• Page End: 521
• Publication Date: 2019-01-14
• Subjects: piezoelectric, -- crystal, -- electrical properties, -- sensor; Electrical engineering -- Congresses; Physics -- Congresses; Materials -- Research -- Congresses; Materials science -- Congresses; 620.11
• DOI: 10.1557/adv.2019.16
• Languages: English
• ISSNs: 2059-8521

Abstract

ABSTRACT: Transport mechanisms in structurally ordered piezoelectric Ca3 TaGa3 Si2 O14 (CTGS) single crystals are studied in the temperature range of 1000-1300 °C by application of the isotope 18 O 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.