Ultrasonic relaxation of some CdO boro-tellurate glasses

Abstract

50B2O3–(50-x)TeO2–xCdO glass system, with x = 0, 10, 20, 30, 40, and 50 mol% have been prepared, to measure the longitudinal ultrasonic attenuation at frequencies of 2, 4, 6, and 14 MHz in the temperature range from 120 to 300 K. Well-defined broad peaks of the absorption curves were observed at different temperatures depending on the glass composition and the operating frequency. The maximum peaks shifted to higher temperatures with the increase of the operating frequency implying the presence of some kind of relaxation process. This process is suggested as due to the thermally activated relaxation process. The variation of the average activation energy of the process mainly depends on the CdO mol% content. Such dependence was analyzed in terms of the loss of standard linear solid type, with low dispersion and a broad distribution of Arrhenius type relaxation with temperature independent relaxation strength. The obtained acoustic activation energy values were quantitatively interpreted in terms of the number of loss centers (number of oxygen atoms that vibrate in the double well potential).