Magnetocaloric properties of Nd(x)Gd(5-x)Si(4)Mn(0.5)Cr(0.)5 (x=0.5, 1, 1.5)

초록

In this work, the magnetocaloric effect (MCE) of NdxGd5-xSi4M1 (x = 0.5, 1, 1.5, M: Cr and Mn) compounds were evaluated. The compounds consisted of multiple phases: (Nd, Gd)(5)Si-4, (Nd, Gd)(5)Si-3, GdMnSi and Cr with (Nd, Gd)(5)Si-4 as the main phase. The addition of Mn produced the ferromagnetic GdMnSi impurity phase while suppressing nucleation of the antiferromagnetic GdSi phase, which improves MCE properties. All the compounds underwent a second-order transition whose transition temperature decreased with increasing Nd fraction, allowing T-C to be tailored as required. The Delta S-M vertical bar(pk) values for NdxGd5-xSi4M1 are 4.2 J kg(-1) K-1 (at 310 K) for x = 0.5, 3.5 J kg(-1) K-1 (at 294 K) for x = 1.0, and 3.28 J kg(-1) K-1 (at 273 K) for x = 1.5 with a field change of 0-3 T. The maximum values of Delta T-ad were 0.73 K (at 273 K) for x = 0.5, 1 K (at 292 K) for x = 1.0, and 1.35 K (at 315 K) for x = 1.5 with a field change of 0-0.8 T, respectively. Thus, although the MCE properties of these compounds were inferior compared with those of Gd, these compounds exhibit a wider operating window and have potential application in a composite refrigerant for the active magnetic refrigeration cycle.

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