Fabrication of La0.67Ca0.33MnO3 magnetocaloric materials with penetrative pores by freeze casting
Magnetocaloric materials can hardly be fabricated into porous structures via conventional mechanical processing methods due to their intrinsic brittleness.Here we successfully fabricated La0.67Ca0.33 MnO3(LCMO)magnetocaloric materials with highly ordered pores via freeze casting.The influences of LCMO solid content on the microstructure,crystal structure,compositional distribution and magnetic properties of the freeze-cast samples were intensively studied by means of transmission electron microscope,scanning electron microscope,X-ray diffractometer,energy dispersive spectrometer and physical property measurement system.It has been found that the freeze-cast LCMO samples are characterized by tunable porosity,uniform chemical distribution and absence of secondary phases.Besides,an isothermal entropy change of 2.5 J·kg-1·K-1 is obtained in the freeze-cast LCMO samples under a field change of 0～1 T,which is comparable to that of the benchmark Gd magnetocaloric material.Therefore,the present work offers a new strategy for the fabrication of magnetocaloric materials with complex geometries,which may promote the practical application of the green and energy-efficient magnetic refrigeration technology.
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