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

• Published in: Materials Vol. 12; no. 18; p. 2877
• Main Authors: Xu, Lingfeng, Qian, Chengyuan, Ai, Yongchang, Su, Tong, Hou, Xueling
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 06.09.2019; MDPI
• Subjects: (Gd0.73Tb0.27)1−yFey; Adiabatic flow; adjustable Curie temperature; Curie temperature; Doping; Gadolinium base alloys; Gd1−xTbx; Heat; Heat treatment; low magnetic field; Magnetic fields; Magnetic properties; Magnetism; magnetocaloric effect; Measurement methods; Phase transitions; low magnetic field; Gd1−xTbx; adjustable Curie temperature; magnetocaloric effect; (Gd0.73Tb0.27)1−yFey
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma12182877

In this paper, the magnetocaloric properties of Gd Tb alloys were studied and the optimum composition was determined to be Gd Tb . On the basis of Gd Tb , 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 Gd Tb ( = 0~0.4) and (Gd Tb ) Fe ( = 0~0.15), and the isothermal magnetic entropy (ΔS ) was also used as a reference parameter for evaluating the magnetocaloric properties of samples together with ΔT . In Gd Tb alloys, the Curie temperature (T ) decreased from 293 K ( = 0) to 257 K ( = 0.4) with increasing Tb content, and the Gd Tb 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 (Gd Tb ) Fe ( = 0~0.15) alloys increased significantly from 276 K ( = 0) to 281 K ( = 0.15), and a good magnetocaloric effect was maintained. The annealing of alloys (Gd Tb ) 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.