Elastic anisotropy and magnetic phase transition of yttrium garnet ferrite

Temperature dependences of elastic moduli describing elastic anisotropy in the rage from room temperature to 600 °C are shown. These temperature dependences are in agreement with available values of elastic moduli and temperature coefficients of the elastic moduli at room temperature. They are in agreement with modern quasi-harmonic theory of crystal lattices. Near 285 °C critical changes of effective elastic moduli due to magnetic phase transition are observed. A correlation was made between experimental and theoretical critical changes of longitudinal and transverse elastic wave velocities for different crystallographic directions. It is proved that the critical change of ultrasound wave velocities of this crystal is connected with the single-ion magnetostriction.