Phase Deconvolution of Multiphasic Materials by the Universal Scaling of the Magnetocaloric Effect

Abstract

Multiphase magnetocaloric materials result from design, where different phases are combined in a composite, or residual phases in the production of the material. The universal scaling of the magnetocaloric effect, commonly used for the study of single-phase second-order phase transitions, shows distortions when applied to multiphase materials with phases that undergo second-order phase transitions. In this work, universal scaling has been applied to a composite with coexistent Gd and Gd₇Pd₃ phases with comparable magnetocaloric responses and Curie temperatures separated by ~ 45 K. The biphasic nature of the sample leads to distortions in universal scaling that have been exploited to deconvolute the magnetocaloric response of each phase. The phase ratio has been obtained through the deconvoluted magnetocaloric responses, and the results are comparable to those from x-ray diffraction refinement. This procedure allows the prediction of the response of a desired pure phase even in the presence of residual magnetic contributions.