Material-based figure of merit for caloric materials

• Published in: Journal of applied physics Vol. 123; no. 3
• Main Authors: Griffith, L. D., Mudryk, Y., Slaughter, J., Pecharsky, V. K.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 21.01.2018; American Institute of Physics (AIP)
• Subjects: Ambient temperature; Applied physics; Cooling; Entropy; Figure of merit; MATERIALS SCIENCE; Refrigeration; Temperature effects
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.5004173

The efficient use of reversible thermal effects in magnetocaloric, electrocaloric, and elastocaloric materials is a promising avenue that can lead to a substantially increased efficiency of refrigeration and heat pumping devices, most importantly, those used in household and commercial cooling applications near ambient temperature. A proliferation in caloric material research has resulted in a wide array of materials where only the isothermal change in entropy in response to a handful of different field strengths over a limited range of temperatures has been evaluated and reported. Given the abundance of such data, there is a clear need for a simple and reliable figure of merit enabling fast screening and down-selection to justify further detailed characterization of those material systems that hold the greatest promise. Based on the analysis of several well-known materials that exhibit vastly different magnetocaloric effects, the Temperature averaged Entropy Change is introduced as a suitable early indicator of the material's utility for magnetocaloric cooling applications, and its adoption by the caloric community is recommended.