Exploring dielectric and AC conduction characteristics in elemental selenium glass modified with silver halides.

In this research work, we have examined the influence of silver halide doping on the dielectric dispersion and AC conduction of elemental selenium. The in-depth investigation shows that when the dopant silver halides are incorporated, there are noticeable changes in the parent selenium's dielectric constant (ε'), dielectric loss (ε''), and AC conductivity (σ ac). When we frame the discussion of the obtained results with the relevant transport models, we found that in pure selenium and Se95(AgI)5, conduction is primarily due to polaron hopping and follows the correlated barrier hopping (CBH) model. In contrast, Se95(AgBr)5 predominantly exhibits non-overlapping small polaron tunneling (NSPT). Interestingly, Se95(AgCl)5 demonstrates both NSPT and CBH conduction mechanisms, depending on the temperature range: NSPT is dominant between 303 K and 313 K, while CBH prevails from 318 K to 338 K. Additionally, our findings revealed the presence of both the Meyer-Neldel rule (MNR) and its reverse in the prepared silver halide chalcogenide alloys. The best optimization of dielectric constant and loss is observed for silver iodide as compared to silver chloride and silver bromide. Comparison with other silver-containing chalcogenide glasses indicates the better dielectric performance of the present silver halides containing selenium.

Thermal analysis of novel third-generation phase-change materials with zinc as a chemical modifier.

The thermal analysis in the present work is done to analyze the glass/crystal phase transformation in a newly synthesized glassy system (i.e., glassy SeTeSnZn alloys) consisting of chalcogenides Se and Te as major elements, Sn as a third element of the parent alloy and Zn as a chemical modifier. The role of increasing the Zn concentration at the cost of Se has been understood by correlating the kinematics of structural relaxation during the glass transition phenomenon and devitrification during the crystallization phenomenon in the chalcogenide glasses (ChGs) of the quaternary STSZ [i.e., Se78-x Zn x Te20Sn2 (0 ≤ x ≤ 6)] system and their different physicochemical properties. A noticeable rise in the crystallization rate is observed after the addition of Zn in the parent SeTeSn glass. With the rise in the zinc content, the values of average heat of atomization and overall mean bond energy are found to be decreased with the decrease in cohesive energy of samples. An inverse correlation is observed between the thermal stability parameter and the enthalpy released during the glass/crystalline phase transformation.