Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

Attenuation and phase velocity of ultrasound have been measured in strontium fluoride single crystal doped with chromium in the temperature range of 4 – 185 K at 56 -162 MHz. Anomalies have been found for all the normal modes corresponding to the non-vanishing elastic moduli of a cubic crystal. Interpretation of the observed anomalies has been done in the frame work of relaxation in the system of Jahn-Teller (JT) complexes CrF₈ subject to full T_2g X (e_g+t_2g)JT problem. Relaxation time has been calculated from the experimental data on ultrasonic attenuation and adiabatic and isothermal contributions of the impurity subsystem to the total elastic moduli have been obtained.