Tunable Magnetocaloric Properties of Gd-Based Alloys by Adding Tb and Doping Fe Elements

Lingfeng Xu; Chengyuan Qian; Yongchang Ai; Tong Su; Xueling Hou

doi:10.3390/ma12182877

Tunable Magnetocaloric Properties of Gd-Based Alloys by Adding Tb and Doping Fe Elements

Materials (Basel). 2019 Sep 6;12(18):2877. doi: 10.3390/ma12182877.

Authors

Lingfeng Xu^{1

2}, Chengyuan Qian^{1

2}, Yongchang Ai^{1

2}, Tong Su^{1

2}, Xueling Hou^{3

4}

Affiliations

¹ Laboratory for Microstructures of Shanghai University, Shanghai 200444, China.
² School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China.
³ Laboratory for Microstructures of Shanghai University, Shanghai 200444, China. xlhou@staff.shu.edu.cn.
⁴ School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China. xlhou@staff.shu.edu.cn.

Abstract

In this paper, the magnetocaloric properties of Gd_1-xTb_x alloys were studied and the optimum composition was determined to be Gd_0.73Tb_0.27. On the basis of Gd_0.73Tb_0.27, the influence of different Fe-doping content was discussed and the effect of heat treatment was also investigated. The adiabatic temperature change (ΔT_ad) 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 Gd_1-xTb_x (x = 0~0.4) and (Gd_0.73Tb_0.27)_1-yFe_y (y = 0~0.15), and the isothermal magnetic entropy (ΔS_M) was also used as a reference parameter for evaluating the magnetocaloric properties of samples together with ΔT_ad. In Gd_1-xTb_x alloys, the Curie temperature (T_c) decreased from 293 K (x = 0) to 257 K (x = 0.4) with increasing Tb content, and the Gd_0.73Tb_0.27 alloy obtained the best adiabatic temperature change, which was ~3.5 K in a magnetic field up to 1.2 T (T_c = 276 K). When the doping content of Fe increased from y = 0 to y = 0.15, the T_c of (Gd_0.73Tb_0.27)_1-yFe_y (y = 0~0.15) alloys increased significantly from 276 K (y = 0) to 281 K (y = 0.15), and a good magnetocaloric effect was maintained. The annealing of alloys (Gd_0.73Tb_0.27)_1-yFe_y (y = 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_c. This study is of great significance for the study of magnetic refrigeration materials with adjustable Curie temperature in a low magnetic field.

Keywords: (Gd0.73Tb0.27)1−yFey; Gd1−xTbx; adjustable Curie temperature; low magnetic field; magnetocaloric effect.