The giant magnetocaloric effect, in which large thermal changes are induced in a material on the application of a magnetic field, can be used for refrigeration applications, such as the cooling of systems from a small to a relatively large scale. However, commercial uptake is limited. We propose an approach to magnetic cooling that rejects the conventional idea that the hysteresis inherent in magnetostructural phase-change materials must be minimized to maximize the reversible magnetocaloric effect. Instead, we introduce a second stimulus, uniaxial stress, so that we can exploit the hysteresis. This allows us to lock-in the ferromagnetic phase as the magnetizing field is removed, which drastically removes the volume of the magnetic field source and so reduces the amount of expensive Nd-Fe-B permanent magnets needed for a magnetic refrigerator. In addition, the mass ratio between the magnetocaloric material and the permanent magnet can be increased, which allows scaling of the cooling power of a device simply by increasing the refrigerant body. The technical feasibility of this hysteresis-positive approach is demonstrated using Ni-Mn-In Heusler alloys. Our study could lead to an enhanced usage of the giant magnetocaloric effect in commercial applications.
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http://dx.doi.org/10.1038/s41563-018-0166-6 | DOI Listing |
ACS Appl Mater Interfaces
December 2024
School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Magnetocaloric high-entropy alloys (HEAs) have recently garnered significant interest owing to their potential applications in magnetic refrigeration, offering a wide working temperature range and large refrigerant capacity. In this study, we thoroughly investigated the structural, magnetic, and magnetocaloric properties of equiatomic GdDyHoErTm HEAs. The as-cast alloy exhibits a single hexagonal phase, a randomly distributed grain orientation, and complex magnetism.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.
Adiabatic demagnetization refrigeration (ADR) based on the magnetocaloric effect (MCE) is a promising technique to achieve cryogenic temperature. However, magnetic entropy change (Δ), the driving force of ADR, remains far below theoretical -Δ = ln(2 + 1)/ for most magnetic refrigerants. Here, we report giant MCE in orthorhombic EuCl, where a ferromagnetic ground state with excellent single-ion behavior of Eu and free spins has been demonstrated by combining calculations with Brillouin function analysis and magnetic measurements.
View Article and Find Full Text PDFACS Appl Mater Interfaces
October 2024
School of Materials Science and Engineering, UNSW Materials and Manufacturing Futures Institute, The University of New South Wales, Sydney, NSW 2052, Australia.
Nat Commun
October 2024
Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 3, 9747AG, Groningen, The Netherlands.
Magnetic refrigeration, which utilizes the magnetocaloric effect, can provide a viable alternative to the ubiquitous vapor compression or Joule-Thompson expansion methods of refrigeration. For applications such as hydrogen gas liquefaction, the development of magnetocaloric materials that perform well in moderate magnetic fields without using rare-earth elements is highly desirable. Here we present a thorough investigation of the structural and magnetocaloric properties of a novel layered organic-inorganic hybrid coordination polymer Co(OH)(SO)[enH] (enH = ethylenediammonium).
View Article and Find Full Text PDFEntropy (Basel)
September 2024
School of Materials Science & Engineering, South China University of Technology, Guangzhou 510640, China.
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