Influence of low temperature truncated calorimetric data on the determination of the magnetocaloric effect of biphasic materials

Abstract It has recently been found that, for single phase materials, the truncation of the low temperature part of heat capacity curves produces a non-monotonic temperature dependent error in the calculated specific isothermal entropy change ( Δ s T ) and adiabatic temperature change ( Δ T S ). However, it was demonstrated that there is a certain initial temperature for which the errors are zero, regardless of the order of the phase transition. This work extends the demonstration to materials with two non-interacting magnetic phases. It is shown that there exists a temperature region close to the transition temperature of one phase for which the truncation of the curves produce a large error in the calculated Δ s T and Δ T S . Away from the vicinity of the phase transition of the phases, it is possible to minimize the errors of the results by choosing a specific initial temperature for integration. A systematic study of the influence of the phase fraction of the secondary phase and distance between transition temperatures is presented.