Abstract
This paper reports on the langatate (LGT) elastic constants measured from room temperature (25�C) to 1100�C using resonant ultrasound spectroscopy (RUS). The constants were extracted by fitting the resonant peaks with those calculated by Lagrangian mechanics at each temperature where the RUS measurements were taken. In addition, the RUS technique was used to extract the piezoelectric constants in the 25�C to 120�C temperature range. This work also publishes a set of temperature coefficients for the elastic constants up to 1100�C. For the measurements, six parallelepiped LGT samples were aligned, cut, ground, and polished at the University of Maine. The samples were aligned to two different crystal orientations, to increase the reliability of the constant fitting. The extraction of LGT elastic constants up to 1100�C presented in this paper represents a critical step towards the design and fabrication of LGT acoustic wave devices for high temperature and harsh environment applications.
