Thermal expansion and phase transitions in the mixed-crystal system (KBr)1-x(KCN)xbetween 5 and 300K

Abstract

For mixed crystals (KBr)1-x(KCN)x the authors measured the linear thermal expansion between 5 and 300K and studied the structural phase transitions (x=1 and 0.70) and the processes for freezing into the orientational glass state (x=0.5 and 0.25). Below 50K, the thermal expansion coefficients for x=0.70, 0.50 and 0.25 exhibit temperature dependences similar to that of potassium halide crystals. At higher temperatures, for (KBr)0.3(KCN)0.7 they observed two subsequent and continuous phase transitions at Tc approximately=180K and 115K, whereas for (KBr)0.5(KCN)0.5 critical behaviour is only evident around the quadrupolar freezing temperature TF approximately=84K.