Low temperature heat capacity and thermodynamic function of BaZrO3 and PbZrO3

Highlights: • Heat capacity of BaZrO₃ and PbZrO₃ is measured using PPMS from (1.9 to 300) K. • Heat capacity of PbZrO₃ is reported for the first time in the temperature region from (40 to 300) K. • Thermodynamic functions are calculated from (0 to 300) K from heat capacity fitting. • Heat capacity contributions are extracted below 10 K using theoretical model. • Unusual large heat capacity of BaZrO₃ below 2.5 K is due to linear contribution. 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.