Electrical Impedance and Ultrasonic Measurements of Ag₃SI

Abstract

The ultrasonic velocity in the α-quenched phase of Ag₃SI has been measured for the longitudinal wave at 10 MHz over the range from 80 K to room temperature with a pulse echo overlap method. Comparison is made with the results of the previous ultrasonic attenuation measurements. The change in the ultrasonic velocity with temperature is found to be due to the relaxation phenomenon of a thermally activated process and an anharmonicity of the lattice vibration. The electrical impedance has also been measured at frequencies between 10 kHz and 10 MHz over the same temperature range. Anomalous behavior is seen both in the electrical and ultrasonic measurements below about 150 K. The activation energy is estimated for the diffusive motion of Ag⁺ ions and a close agreement between the values deduced from two different experiments is obtained.