Measurement of Third-Order Elastic Moduli of Yttrium Iron Garnet

Abstract

The third-order elastic moduli of yttrium iron garnet (YIG) have been determined from measurements of ultrasonic velocity. A pulsed ultrasonic system which uses a phase comparison principle to measure velocity versus applied stress is described. In units of 1012 dyn/cm2 and for 28°C, the third-order moduli are: C111=−23.3±0.8C112=−7.17±0.6C123=−0.33±1.3C144=−1.48±0.29C155=−3.06±0.14C456=−0.97±0.16.Thermodynamic definitions for the moduli [K. Brugger, Phys. Rev. 133, A1611 (1964)] have been used.