Hard ferromagnets as a new perspective on materials for thermomagnetic power generation cycles

We consider the ways in which magnetically hard materials can be used as the working materials in thermomagnetic power generation (TMG) cycles in order to expand the area in the magnetisation vs. applied field (M - H) plane available for energy conversion. There are 3 parts to this Perspective. First, experiments on commercially available hard ferrites reveal that, while these materials are not yet good TMG candidates, hard ferromagnets with higher thermal conductivity and a greater change of magnetization with temperature could outperform existing TMG materials. Second, computational results indicate that biasing a soft magnet with a hard ferromagnet is essentially equivalent to shifting the M- H loop by an amount proportional to the field of the biasing magnet. Work outputs under biased conditions show a substantial improvement over unbiased cycles, but experimental verification is needed. Third, we discuss the rationale for exploring artificial spin reorientation materials as novel TMG working materials. (c) 2023 Elsevier B.V. All rights reserved.

Automated summary

This article discusses how magnetically hard materials can be used in thermomagnetic power generation (TMG) cycles to expand the energy conversion area in the magnetisation vs. applied field (M - H) plane. Experiments show that hard ferromagnets with higher thermal conductivity and a greater change of magnetization with temperature may outperform existing TMG materials. Computational results suggest that biasin g a soft magnet with a hard ferromagnet is equivalent to shifting the M-H loop. Artificial spin reorientation materials are also explored as potential TMG working materials.