Heat capacity of chromium-tellurium alloy at high temperatures

Abstract

Heat capacities of monoclinic Cr 5Te 8(m) (CrTe 1.528, CrTe 1.576 and CrTe 1.590) and trigonal Cr 5Te 8(tr) (CrTe 1.609) were measured from 220 to 900 K by using an adiabatic scanning calorimeter. Heat capacity anomalies were observed at 841, 842 and 815 K for monoclinic Cr 5Te 8(m) (CrTe 1.528, CrTe 1.576 and CrTe 1.590, respectively) and at 776 K for trigonal Cr 5Te 8(tr) (CrTe 1.609), presumably due to order-disorder of chromium vacancies in chromium tellurides. The transition entropy changes of Cr 5Te 8(m) and Cr 5Te 8(tr) phases obtained in this experiment were smaller than those calculated from the entropy changes due to the partial disordering of chromium vacancies originally limited to every second chromium layer. This fact suggests that the completely-ordered phase is not formed in spite of slowly cooling the sample or that the partially-ordered phase still remains even at the high temperatures at which measurments were made in this study.