Xu Lingfeng, Qian Chengyuan, Ai Yongchang, Su Tong, Hou Xueling
Laboratory for Microstructures of Shanghai University, Shanghai 200444, China.
School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China.
Materials (Basel). 2019 Sep 6;12(18):2877. doi: 10.3390/ma12182877.
In this paper, the magnetocaloric properties of GdTb alloys were studied and the optimum composition was determined to be GdTb. On the basis of GdTb, the influence of different Fe-doping content was discussed and the effect of heat treatment was also investigated. The adiabatic temperature change (ΔT) obtained by the direct measurement method (under a low magnetic field of 1.2 T) and specific heat capacity calculation method (indirect measurement) was used to characterize the magnetocaloric properties of GdTb ( = 00.4) and (GdTb)Fe ( = 00.15), and the isothermal magnetic entropy (ΔS) was also used as a reference parameter for evaluating the magnetocaloric properties of samples together with ΔT. In GdTb alloys, the Curie temperature (T) decreased from 293 K ( = 0) to 257 K ( = 0.4) with increasing Tb content, and the GdTb alloy obtained the best adiabatic temperature change, which was 3.5 K in a magnetic field up to 1.2 T (T = 276 K). When the doping content of Fe increased from = 0 to = 0.15, the T of (GdTb)Fe ( = 00.15) alloys increased significantly from 276 K ( = 0) to 281 K ( = 0.15), and a good magnetocaloric effect was maintained. The annealing of alloys (GdTb)Fe ( = 0~0.15) at 1073 K for 10 h resulted in an average increase of 0.3 K in the maximum adiabatic temperature change and a slight increase in T. This study is of great significance for the study of magnetic refrigeration materials with adjustable Curie temperature in a low magnetic field.
本文研究了GdTb合金的磁热性能，确定最佳组成为GdTb。在GdTb的基础上，讨论了不同Fe掺杂含量的影响，并研究了热处理的效果。通过直接测量法（在1.2 T的低磁场下）和比热容计算法（间接测量）获得的绝热温度变化（ΔT）用于表征GdTb（x = 00.4）和（GdTb）Fe（x = 00.15）的磁热性能，等温磁熵变（ΔS）也与ΔT一起用作评估样品磁热性能的参考参数。在GdTb合金中，随着Tb含量的增加，居里温度（Tc）从293 K（x = 0）降至257 K（x = 0.4），GdTb合金获得了最佳的绝热温度变化，在高达1.2 T的磁场中（Tc = 276 K）约为3.5 K。当Fe的掺杂含量从x = 0增加到x = 0.15时，（GdTb）Fe（x = 00.15）合金的Tc从276 K（x = 0）显著增加到281 K（x = 0.15），并保持了良好的磁热效应。（GdTb）Fe（x = 00.15）合金在1073 K下退火10 h，最大绝热温度变化平均增加0.3 K，Tc略有增加。本研究对于低磁场下居里温度可调的磁制冷材料的研究具有重要意义。
