磁致冷材料研究进展

Development of Magnetic Refrigerant Materials

介绍了磁致冷材料磁热效应的表征方法,概述了国内外各温度区间磁致冷材料的研究进展。在20K以下温区,磁致冷材料研究主要集中在具有高导热率、低点阵热容和极低有序化温度的石榴石,如Gd3Ga5O12(GGG),Dy3Al5O12(DAG),Gd3Ga5-xFexO12(GGIG)及Er基磁致冷材料;20K^77K温度区间,磁致冷材料研究主要集中在重稀土金属间化合物中,如(Dy1-xErx)Al2复合材料等;在室温附近,具有大磁热效应的磁致冷材料以稀土Gd,Gd5(SixGe1-x)4(0≤x≤0.5)和MnFeP1-xAsx(0.15≤x≤0.66)合金为代表,特别是Gd5Si2Ge2(TC=274K)和MnFeP0.45As0.55(TC=300K)合金,在磁场5T下具有巨磁热效应,是Gd的2倍以上。总结了各温度区间磁致冷材料的选择依据。重点评述了室温磁致冷材料的最新研究成果,展望了室温磁致冷材料的发展前景。

Methods to express the magnetocaloric effect (MCE) and a thermodynamic theory of NICE have been introduced, and the development of magnetic refrigerant materials for application over various temperature ranges have been reviewed. For temperatures around 20 K, the development of magnetic refrigerant materials mainly focuses on the garnets with high thermal conductivity, low lattice heat fusion and very low ordering temperatures, for instance: Gd3Ga5O12(GGG), Dy3Al5O12 (DAG), Gd3Ga5-xFexO12 (GGIG), and Er base magnetic refrigerant materials. For the temperature range 20 Ksimilar to77 K, the development is centered on metallic compounds of heavy rare earth metals, for example: (Dy-Er) Al compound materials. In the vicinity of room temperature, the magnetic refrigerant materials with high magnetocaloric effect of which the rare earth Gd, Gd-5(SixGe1-x)(4)(0less than or equal toxless than or equal to0.5) and MnFeP1-xAsx (0.15less than or equal toxless than or equal to0.66) are representative, especially Gd5Si2Ge2 (T-C=274 K) and MnFeP0.45As0.55 (T-C=300 K) are likely candidates. These alloys exhibit tremendous magnetocaloric effects at the field of 5 T, more than twice that of Gd. The selection principle for magnetic refrigerant materials for operation over various temperature ranges has been summarized. The latest achievements of magnetic refrigerant materials at room temperature have been specially reviewed, and the development trend of magnetic refrigerant materials at room temperature has been outlined.