Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Contributions to anelasticity in langasite and langatate



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


Maximization of the quality factors Q of langasite (LGS) and langatate (LGT) is necessary for optimal performance of acoustic resonators of these materials in frequency-control and high-temperature sensing applications. In this report, measurements and least-squares analysis of 1/Q as a function of ultrasonic frequency and temperature (up to 750~K) of undoped LGS and LGT reveal a superposition of physical effects, including point defect relaxations and intrinsic phonon-phonon loss. In LGS, these effects are superimposed on a large temperature-dependent background with weak frequency dependence that is understood to arise from a relaxation process with a distribution of activation energies. This distributed relaxation is suggested to be consistent with anelastic kink migration. No evidence for a significant background of this form is found in the more recently fabricated LGT crystal. The analysis of the frequency- and temperature-dependence of 1/Q of LGT indicates that, at near-ambient temperatures, the damping in this specimen is close to the intrinsic limit determined by phonon-phonon interactions. Piezoelectric/carrier relaxation, which must occur at sufficiently elevated temperatures, is not found to be a significant contribution to $1/Q, relative to defect-related contributions, in either LGS or LGT in the measured range of temperatures.
Physical Review B


acoustic resonance, anelasticity, dislocation damping, high-temperature sensors, kink migration, langasite, langatate, phonon-phonon damping, point defect relaxation, quality factor, ultrasonic attenuation


Johnson, W. , Kim, S. , Rivenbark, C. and Uda, S. (2011), Contributions to anelasticity in langasite and langatate, Physical Review B, [online], (Accessed April 16, 2024)
Created December 30, 2011, Updated November 10, 2018