Investigation on the magnetocaloric effect in DyNi2, DyAl2 and Tb1−Gd Al2 (n=0, 0.4, 0.6) compounds

Abstract

a b s t r a c tThe magnetocaloric effect (MCE) in the DyNi 2 , DyAl 2 and Tb 1Àn Gd n Al 2 (n ¼ 0, 0.4, 0.6) was theoretically investigated in this work. The DyNi 2 and DyAl 2 compounds are described considering a model Hamiltonian which includes the crystalline electrical field anisotropy. The anisotropic MCE was calculated changing the magnetic field direction from /111S to /0 0 1S in DyNi 2 and from /10 0S to /0 11S in DyAl 2 . The influence of the second-and first-order spin-reorientation phase transitions on the MCE that occurs in these systems is discussed. For the calculations of the MCE thermodynamic quantities in the Tb 1Àn Gd n Al 2 systems we take into account a two sites magnetic model, and good agreement with the available experimental data was obtained.

Texture-induced enhancement of the magnetocaloric response in melt-spun DyNi2 ribbons

“…For l o DH ¼ 2 T, the as-quenched ribbons exhibit a high value for the maximum magnetic entropy change jDS M peak j ¼ 13.5 J kg À1 K À1 at 21.5 K, as well as a full width at half maximum for the jDS M (T)j curve of dT FMHW ¼ 16 K (between 13 and 29 K). It is important to note that jDS M peak j is 25% higher than the value attained for the bulk polycrystalline sample, for which 34 On the other hand, the X-ray pattern [see Fig. 1(a)] provides evidence that the ribbons are clearly textured, thus it seems likely that the special MC properties of DyNi 2 ribbons could be related to a combination of texture effects (extrinsic feature) and anisotropic MCE response (intrinsic feature).…”

Magnetothermal properties of TmxDy1−xARibeiro1, Alho2, Oliveira3 et al. 2021Journal of Alloys and CompoundsSelf Cite7000View full textAdd to dashboardCite

“…The three studied compounds exhibit high magnetocaloric effects between 47.9 K for 𝑥 = 0.25 and 15.8 K and for 𝑥 = 0.75, respectively [32]. It was predicted that DyAl 2 should exhibit strong anisotropic MCE around its spin reorientation temperature, TR, exceeding conventional magnetocaloric effect around its Curie temperature, TC [33]. For TmAl 2 there is experimental evidence [34] of a spin reorientation transition below 𝑇 𝐶 , but it vanishes in the investigated intermediate Tm 𝑥 Dy 1−𝑥 Al 2 compounds with 𝑥 = 0.25, 0.50 and 0.75 [32].…”