Tuning the Magnetocaloric Properties of the La(Fe,Si)13 Compounds by Chemical Substitution and Light Element Insertion

Abstract

LaFe13−xSix compounds exhibit a giant magnetocaloric effect and they are considered as a good magnetocaloric working substance for an environmentally friendly cooling technique. Nevertheless as the Curie temperature TC is around 200 K, it is necessary to tune TC near room temperature for magnetic refrigeration. In this work we present a review of the various methods of synthesis and shaping of the LaFe13−xSix type compounds as well as the influence of chemical substitution, light element insertion or combination of both on TC, magnetic entropy and adiabatic temperature variation (ΔSM and ΔTad), and stability upon cycling. The advantages and drawbacks of each method of preparation and type of element substitution/insertion are discussed. The implementation of these NaZn13 type materials in active magnetic refrigerator is presented and their performances are compared to that of Gd in prototypes.

Tailoring Negative Thermal Expansion via Tunable Induced Strain in La–Fe–Si-Based Multifunctional Material

“…The La­(Fe 1– x ,Si x ) 13 -derived compounds are very well known for their giant magnetocaloric effect and NTE behavior. ,,,,,,− Their crystal structure is cubic with Fm-3c space group, and they display a ferromagnetic-to-paramagnetic (FM-PM) isostructural transition, corresponding to a low-temperature high-magnetization (ordered) state that evolves into a high-temperature low-magnetization (disordered) state as the temperature is increased across their T C . Along these transitions, the crystal structure is retained, but the unit cell volume contracts by 3000–30,000 ppm typically over a <50 K temperature interval. ,,,− To act as compensators, NTE materials should have a more gradual change of volume over a larger temperature window, akin to the typical changes on standard PTE materials.…”

A Short Review on the Evolution of Magnetocaloric La(Fe,Si)13 and Its Fabrication through Melt Spinning

“…66 There are various techniques for the preparation of LaFe 13−x Si x compounds such as arc-melting, induction melting, ball milling, melt spinning, hot pressing, spark plasma sintering, etc. 67 The mixing of rare earth materials to achieve the nearroom-temperature Curie transition temperature is the main challenge during the preparation of LaFe 13−x Si x . 64 Ball milling is one technique that may be used to decrease the particle size of bulk materials; 68 however, it is a batch process that makes use of surfactants, which can inhibit magnetic response.…”

“…To reduce the diffusion route, they primarily rely on a reduction in particle size and close contact between the various phases formed during casting. 67 From the literature, it is evident that most of the methods used for preparation of magnetocaloric La(Fe,Si) 13 are physical-or vacuum-based deposition methods which are not cost-effective. 3 The commercialization of magnetic refrigeration or scaling up to an industrial level needs low-cost methods to be employed.…”

Magnetocaloric properties in (La,R)(Fe,Mn,Si)13H (R = Ce and Pr)—toward a better alloy design that results in a reduction in volume of permanent magnets and the establishment of long-term reliability in cooling systems

“…Meanwhile, the proposed compound system has a shortcoming of the splitting phenomenon, which is correlated with the diffusion of hydrogens [24,25,[32][33][34]. To overcome this drawback in long-term reliability, the alloy design should now admit a co-doping technique of rare-earth elements and Mn to La(Fe,Si) 13 H systems [34][35][36][37]. Although this approach brings about the laborious complexity, degrees of freedom are provided in the alloy design.…”