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Magnetic refrigeration

About: Magnetic refrigeration is a(n) research topic. Over the lifetime, 6772 publication(s) have been published within this topic receiving 141558 citation(s). more

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Journal ArticleDOI
09 Sep 1993-Nature
Abstract: MAGNETIC materials of mesoscopic dimensions (a few to many thousands of atoms) may exhibit novel and useful properties such as giant magnetostriction, magnetoresistivity and magnetocaloric effects1–4. Such materials also allow one to study the transition from molecular to bulk-like magnetic behaviour. One approach for preparing mesoscopic magnetic materials is to fragment bulk ferromagnets; a more controllable method is to take a 'bottom-up' approach, using chemistry to grow well defined clusters of metal ions5,6. Lis7 has described a twelve-ion manganese cluster in which eight of the Mn ions are in the +3 oxidation state (spin S=2) and four are in the +4 state (S=3/2). These ions are magnetically coupled to give an S=10 ground state8, giving rise to unusual magnetic relaxation properties8,9. Here we report that the magnetization of the Mn12 cluster is highly anisotropic and that the magnetization relaxation time becomes very long below a temperature of 4 K, giving rise to pronounced hysteresis. This behaviour is not, however, strictly analogous to that of a bulk ferromagnet, in which magnetization hysteresis results from the motion of domain walls. In principle, a bistable magnetic unit of this sort could act as a data storage device. more

3,189 citations

Journal ArticleDOI
Abstract: The recent literature concerning the magnetocaloric effect (MCE) has been reviewed. The MCE properties have been compiled and correlations have been made comparing the behaviours of the different families of magnetic materials which exhibit large or unusual MCE values. These families include: the lanthanide (R) Laves phases (RM2, where M = Al, Co and Ni), Gd5(Si1−xGex)4 ,M n(As1−xSbx), MnFe(P1−xAsx), La(Fe13−xSix) and their hydrides and the manganites (R1−xMxMnO3, where R = lanthanide and M = Ca, Sr and Ba). The potential for use of these materials in magnetic refrigeration is discussed, including a comparison with Gd as a near room temperature active magnetic regenerator material. (Some figures in this article are in colour only in the electronic version) more

2,726 citations

Journal ArticleDOI
10 Jan 2002-Nature
TL;DR: The discovery of a large magnetic entropy change is reported in MnFeP0.45As0.55, a material that has a Curie temperature of about 300 K and which allows magnetic refrigeration at room temperature, attributed to a field-induced first-order phase transition enhancing the effect of the applied magnetic field. more

Abstract: Magnetic refrigeration techniques based on the magnetocaloric effect (MCE) have recently been demonstrated as a promising alternative to conventional vapour-cycle refrigeration1. In a material displaying the MCE, the alignment of randomly oriented magnetic moments by an external magnetic field results in heating. This heat can then be removed from the MCE material to the ambient atmosphere by heat transfer. If the magnetic field is subsequently turned off, the magnetic moments randomize again, which leads to cooling of the material below the ambient temperature. Here we report the discovery of a large magnetic entropy change in MnFeP0.45As0.55, a material that has a Curie temperature of about 300 K and which allows magnetic refrigeration at room temperature. The magnetic entropy changes reach values of 14.5 J K-1 kg-1 and 18 J K-1 kg-1 for field changes of 2 T and 5 T, respectively. The so-called giant-MCE material Gd5Ge2Si2 (ref. 2) displays similar entropy changes, but can only be used below room temperature. The refrigerant capacity of our material is also significantly greater than that of Gd (ref. 3). The large entropy change is attributed to a field-induced first-order phase transition enhancing the effect of the applied magnetic field. more

2,079 citations

Journal ArticleDOI
Thorsten Krenke1, Eyup Duman1, Mehmet Acet1, Eberhard F. Wassermann1  +3 moreInstitutions (2)
01 Jun 2005-Nature Materials
Abstract: The magnetocaloric effect (MCE) in paramagnetic materials has been widely used for attaining very low temperatures by applying a magnetic field isothermally and removing it adiabatically. The effect can also be exploited for room-temperature refrigeration by using giant MCE materials. Here we report on an inverse situation in Ni-Mn-Sn alloys, whereby applying a magnetic field adiabatically, rather than removing it, causes the sample to cool. This has been known to occur in some intermetallic compounds, for which a moderate entropy increase can be induced when a field is applied, thus giving rise to an inverse magnetocaloric effect. However, the entropy change found for some ferromagnetic Ni-Mn-Sn alloys is just as large as that reported for giant MCE materials, but with opposite sign. The giant inverse MCE has its origin in a martensitic phase transformation that modifies the magnetic exchange interactions through the change in the lattice parameters. more

1,560 citations

A.M. Tishin, Y I Spichkin1Institutions (1)
01 Sep 2003-
Abstract: Introduction Theory Magnetocaloric effect in the phase transition region Methods of investigation of magnetocaloric properties Magnetocaloric effect in 3d metals and their alloys Magnetocaloric effect in amorphous materials Magnetocaloric effect in rare earth metals and their alloys Magnetocaloric effect in intermetallic compounds with rare earth elements Magnetocaloric effect in oxide compounds Magnetocaloric effect in silicides and germanides Magnetocaloric effect in nanosized materials Magnetic refrigeration Conclusions more

1,507 citations

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Topic's top 5 most impactful authors

E.K. Hlil

193 papers, 3K citations

A. Cheikhrouhou

127 papers, 2K citations

Oliver Gutfleisch

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E. Dhahri

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