论文部分内容阅读
较详细地研究了Er2-xCexFe17化合物的结构、磁性和磁熵变。结果表明,轻稀土Ce的掺入虽然没有明显改变Er2Fe17化合物的相结构及其晶格常数,但改变了Er次晶格与Fe次晶格之间的耦合系数,使仍为Th2Ni17型六方结构的Er2-xCexFe17化合物的居里温度可通过成分微调使其处在室温附近。Er2-xCexFe17化合物的λ形(-?SM)-T曲线表明其在居里点附近发生的相变属于二级相变,它使化合物可在较宽温区范围内保持较大的磁熵变。Er2-xCexFe17化合物在x=0.05~0.1范围内具有较大的磁熵变,其在2.0T和5.0T外场下的最大磁熵变达到金属Gd的40%~50%,且其化学性质稳定、制冷温区宽、价格低廉,是一类性价比较高、应用潜力较大的新型低场室温磁制冷工质材料。
The structure, magnetic properties and magnetic entropy change of Er2-xCexFe17 compounds have been investigated in more detail. The results show that although the incorporation of light rare earth Ce does not significantly change the phase structure and lattice constant of Er2Fe17 compound, the coupling coefficient between Er sub-lattice and Fe sub-lattice is changed so that the composition of the hexagonal structure of Th2Ni17 The Curie temperature of the Er2-xCexFe17 compound can be fine-tuned by the composition to be near room temperature. The λ-shaped (-? SM) -T curve of Er2-xCexFe17 shows that its phase transition near the Curie point belongs to the second-order phase transition, which makes the compound maintain a larger magnetic entropy change over a wider temperature range . Er2-xCexFe17 has a large magnetic entropy change in the range of x = 0.05 ~ 0.1. The maximal magnetic entropy change of Er2-xCexFe17 reaches 40% ~ 50% of the metal Gd at 2.0T and 5.0T, and its chemical property is stable. Refrigeration temperature zone wide, low prices, is a kind of high cost, high potential for application of new low-temperature magnetic refrigeration material at room temperature.