Low temperature heat capacity and thermodynamic function of BaZrO3 and PbZrO3

Abstract

BaZrO3 and PbZrO3 are both technologically important functional materials particularly with attracting paraelectric and antiferroelectric properties, respectively. However, the current heat capacity studies on these two compounds are insufficient to understand their intrinsic chemical or physical property on thermodynamics. Herein, we reported heat capacities of BaZrO3 and PbZrO3 measured using a relaxation calorimeter equipped on the Physical Property Measurement System in the temperature range from (1.9 to 300) K. The heat capacity data was fitted to a series of theoretical and empirical models, and the corresponding thermodynamic functions were calculated in the range from (0 to 300) K. The heat capacity contributions were extracted using the theoretical model and fitting parameters, revealing that the unusual large heat capacity of BaZrO3 compared with that of PbZrO3 below about 2.5 K is likely due to the dominant linear heat capacity contribution. Also, the heat capacity of BaZrO3 was compared with those previously reported in literate, and most importantly, the heat capacity of PbZrO3 is the first time reported in the temperature region from (40 to 300) K in this work, as far as we know.