宽温域Mn基反钙钛矿复合磁制冷材料的设计和制备

采用固相合成法高温烧结Mn3SnC和Mn3CuN两种化合物制备出相变温区连续变化的Mn3Sn1-xCuxC1-cNx系列化合物,再将不同相变温区的Mn3Sn1-xCuxC1-xNx化合物进行物理混合制备出反钙钛矿复合磁制冷材料.这种磁制冷材料在室温附近具有"平台"状的磁熵变-温度曲线,与Mn3SnC单体材料相比其磁制冷...

Design and Preparation of Mn-based Antipervoskite Magnetic Refrigerant Composites with Wide Temperature Range

Polycrystalline compounds of Mn₃Sn_1-x Cu _x C_1-x N _x were synthesized by solid-state reaction with Mn₃SnC and Mn₃CuN as raw materials. The phase transition temperature of Mn₃Sn_1-x Cu _x C_1-x N _x continuously changes with the variation of the Mn₃SnC content. The compounds present platform-shaped magnetic entropy-temperature curves around room temperature. Compared with Mn₃SnC, the magnetic cooling temperature range of the compounds changed from 275~285 K to 220~300 K, and the full width at half maximum of magnetic entropy change curve increased from 5 K to 70 K. However, the magnetic entropy of the compounds decreased significantly. The relationship among the maximum of magnetic entropy change, the half-height width of the magnetic entropy change curve for the compounds and the relative cooling power of the monomer materials was acquired. The competition between expanding the cooling temperature range and increasing the magnetic entropy change can be well understood. This quantitative formula is of significance in the field not only for the antiperovskite materials, but also for other magnetic refrigerant composites. In this work a new calculation and prediction method of magnetic refrigerant composites were proposed based on the heat flow curve of monomer material, and it could greatly simplify the design process of composite materials.