The presence of a thermally reversing window in Al–Te–Si glasses revealed by alternating differential scanning calorimetry and electrical switching studies

Alternating differential scanning calorimetric (ADSC) studies and electrical switching experiments have been undertaken on $Al₁₅Te_85-xSi_x$ (2 \leq x \leq 12) system of glasses. These glasses are found to exhibit two crystallization reactions $(T_c1 and T_c2)$, for compositions with x < 8. Above x = 8, a single-stage crystallization is seen. Further, a trough is seen in the composition dependence of nonreversing enthalpy (DHNR), based on which it is proposed that there is a thermally reversing window in $Al₁₅ Te_85-xSi_x$ glasses, in the composition range 4 \leq x \leq 8. Electrical switching studies indicate that $Al₁₅ Te_85-xSi_x$ glasses exhibit a threshold type electrical switching at ON state currents less than 2 mA. Further, the switching voltages are found to increase with the increase in silicon content. It is interesting to note that the start (x = 4) and the end (x = 8) of the thermally reversing window are exemplified by a kink and a saturation in the composition dependence of switching voltages, respectively.