Large magnetocaloric effect in melt-spun LaFe13−xSix

Abstract

A very large value of magnetic entropy change ∣ΔS∣=31J∕kgK was obtained at 201K under 5T in LaFe11.8Si1.2 melt-spun ribbons subjected to a very short-time annealing (2h∕1050°C). This value is much higher than that of a bulk LaFe11.44Si1.56 in this temperature range. The large ∣ΔS∣ is attributed to the first-order thermally induced transition at the Curie temperature TC, and is enhanced even further due to a more homogenous element distribution. With increasing Si concentration, TC is increased and ∣ΔS∣ is decreased due to a weakening or an even disappearance of the first-order magnetic phase transition.

Capturing first- and second-order behavior in magnetocaloricCoMnSi0.92Ge0.08

“…3,11,12,13 These observations are encouraging because one of the major questions is whether it is possible to engineer a material so that the physical properties attractive for application can be maximized (large entropy change due to a 1 st order transition), whilst those that are detrimental (hysteresis) can be suppressed. In this paper we examine the role of hysteresis and its relationship to the strength of the 1 st order transition in the inverse 14 magnetocaloric material CoMnSi 0.92 Ge 0.08 .…”

Reducing extrinsic hysteresis in first-order La(Fe,Co,Si)13 magnetocaloric systems

“…The first two conditions are satisfied in the very interesting class of materials La͑Fe, Si͒ 13 . [2][3][4] What is not widely appreciated is that in a MR cycle the magnetizing and demagnetizing steps are dynamic and the rate of field change is high Ḣ Ͼ 1 T/ s. Therefore understanding the dynamics of the system and the impact on performance when the system is driven out of equilibrium with the thermal bath, are extremely important for application. Here, we demonstrate using the magnetocaloric La͑Fe 1−x−y Co x Si y ͒ 13 materials 5 that the dynamics of heat exchange with the material undergoing a field-driven transition leads to a significant sweep-rate dependent extrinsic magnetic hysteresis.…”

Latent heat of the first-order magnetic transition ofMnFeSi0.33P0.66

“…The discovery of giant MCE in Gd 5 Si 2 Ge 2 by Pecharsky and Gschneidner [5] initiated an extensive search for materials suitable for near-room-temperature applications. Since this discovery, several classes of materials including MnFe(P 1−x As x ) [6], La(Fe,Si) 13 [7,8], and their hydrides [9], Mn(As,Sb), FeRh [10], Heusler alloys [11], and Mn 2 Sb [12] have been proposed as promising candidates for magnetic refrigerants. Some of the materials exhibiting a giant magnetocaloric effect, viz., La(Fe,Si) 13 and MnFe(P 1−x T x ) [with T = Si, Ge, and As], can be tuned for minimal hysteresis loss around the phase transition, which is necessary for its cyclic operation.…”