Ultrasonic attenuation with relaxation at low temperatures of Nd³⁺ doped phosphate glasses for potential solid-state laser applications

The glass set, with varying compositions of (1-x) (0.659 P₂O₅, 0.095 ZnO, and 0.244 PbO), was used to investigate longitudinal ultrasonic attenuation at different frequencies (2 and 14 MHz) and different temperatures (120 and 300 K). The glass samples contained different mole percentages of Nd₂O₃, specifically x = 0.00, 0.0046, 0.0092, 0.0138, and 0.0271. Based on the glass construction and switching frequency in well-defined broad absorption curve reaches its highest points at different temperatures. These peaks shifted to higher temperatures, indicating a relaxing mechanism, as the overall frequency increased. A thermally driven relaxation process led to the development of an approach, that the activation mechanism's average energy was mainly influenced by the mole percent content of Nd₂O₃. The observed diminish of the acoustical energy of activation worth's, quantifiably expressed in terms of the diminished amount of oxygen atoms moving at a double-well potential, that was determined based on the number of loss centers. Such decrease in average activation energy was correlated with the increase in; Bulk elastic modulus, linear expansion coefficient, glass transition temperature and average bond dissociation energy with Nd₂O₃.