High-throughput direct measurement of magnetocaloric effect based on lock-in thermography technique

Abstract

We demonstrate a high-throughput direct measurement method for the magnetocaloric effect (MCE) by means of a lock-in thermography (LIT) technique. This method enables systematic measurements of the magnetic-field and operation-frequency dependences of the temperature change induced by the MCE. This is accomplished in a shorter time compared with conventional adiabatic temperature measurement methods. The direct measurement based on LIT is free from any possible miscalculations and errors arising from indirect measurements using thermodynamic relations. Importantly, the LIT technique makes simultaneous MCE measurements of multiple materials possible without increasing measurement time, realizing high-throughput investigations of the MCE. By applying this method to Gd, we obtain the MCE-induced temperature change of 1.84 $\pm$ 0.11 K under a modulation field of 1.0 T and modulation frequency of 0.5 Hz at a temperature of 300.5 $\pm$ 0.5 K, offering evidence that the LIT method gives quantitative results.