(1. State Key Laboratory for Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China) (2. Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy ofSciences, Beijing 100190, China)
Keywords:
-
CLC:
PACS:
-
DOI:
10.7502/j.issn.1674-3962.2013.02.03
DocumentCode:
Abstract:
In this article, the investigation progress is reviewed in magnetic field and temperature dependences of the magnetic properties and magnetocaloric effects (MCEs) for RPdAl compounds with the orthorhombic TiNiSitype (LTM) and the hexagonal ZrNiAltype (HTM) structures. The LTMRPdAl (R=Gd, Tb, Dy, Ho and Er) compounds are found to be antiferromagnet with the Néel temperature TN=31, 45, 21, 10 and 10 K, respectively. It has been confirmed that the HTMRPdAl (R=Tb, Ho and Er) compounds undergo the antiferromagnetic (AFM)toparamagnetic (PM) transition at TN=43, 12 and 5 K, while the HTMRPdAl (R=Gd and Dy) compounds undergo the ferromagnetic (FM)toPM transition at their respective Curie temperature, which is TC =49 K and 25 K, respectively. A fieldinduced metamagnetic transition from AFM to FM state is observed below TN in the antiferromagnetic RPdAl. For the HTMRPdAl (R=Ho and Er) compounds, a small magnetic field can induce an FMlike state due to a weak AFM coupling, which leads to a high saturation magnetization, and gives rise to a large MCE around TN. The maximum value of magnetic entropy change (ΔSM) reaches -206 and -243 J/kg·K with a refrigerant capacity (RC) value of 386 and 299 J/kg around TN for a field change of 0~5 T, respectively. The large ΔSM and considerable RC suggest that HTMRPdAl may be an appropriate candidate for magnetic refrigerant in low temperature ranges.