Novel fabrication of honeycomb-like magnetocaloric regenerators via a self-organization process

The geometry of a magnetocaloric regenerator (MR) is crucial to the heat exchange efficiency and the performance of a magnetic refrigerator. Here we proposed a new and facile way to produce monolithic La0.67Ca0.33MnO3 MRs with highly ordered and unidirectional oriented microchannels. This is realized by a selforganization process of alginate sol, which does not require specific processing equipment and hence is wellsuited for large-scale production. The average diameter and total porosity of the well-defined microchannels can be adjusted in the range of 71.5-156.3 mu m and 15.3%-21.5%, respectively. The orthorhombic perovskite structure is retained in the sintered MRs without any detectable secondary phase. Besides, the sintered MRs exhibit a significantly higher isothermal entropy change than the original La0.67Ca0.33MnO3 powders due to an increase in the grain size. Consequently, our study may trigger a breakthrough in the large-scale production of monolithic MRs with desirable geometries for magnetic refrigerators.