Transient heat-flux method for measuring heat capacity: Examples from Cu and VO2

Many quantum materials undergo phase transitions above room temperature. However, thermodynamic evidence of these phase transitions is relatively scarce. For instance, detailed specific heat anomalies have rarely been reported for the transitions. In addition to considering intrinsic factors that obscure the thermodynamic manifestation of relevant degrees of freedom, it is also important to revisit measurement techniques based on firmly established physical principles. In this study, we introduce a transient heat-flux method for measuring heat capacity of solids, and report a specific heat anomaly in VO₂, along with the reproduction of the standard specific heat capacity data of Cu. At present, our method is capable of measuring heat capacities ranging from 1 J/mol⋅K to 400 J/mol⋅K with an uncertainty of 5% across a temperature range from room temperature to 100 °C.