title: Inverse magnetocaloric effect in ferromagnetic Ni-Mn-Sn alloys.
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.
authors.affiliation: Fachbereich Physik, Experimentalphysik, Universität Duisburg-Essen, D-47048 Duisburg, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Krenke
authors.forename: Eyüp
authors.initials: E
authors.lastname: Duman
authors.forename: Mehmet
authors.initials: M
authors.lastname: Acet
authors.forename: Eberhard F
authors.initials: EF
authors.lastname: Wassermann
authors.forename: Xavier
authors.initials: X
authors.lastname: Moya
authors.forename: Lluis
authors.initials: L
authors.lastname: Mañosa
authors.forename: Antoni
authors.initials: A
authors.lastname: Planes
mesh_terms: D000497:Alloys / Q000032:analysis / Q000737:chemistry / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D004574:Electromagnetic Fields; D004735:Energy Transfer; D008280:Magnetics; D008345:Manganese / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects; D008422:Materials Testing; D009532:Nickel / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects; D011829:Radiation Dosage; D013696:Temperature; D014001:Tin / Q000032:analysis / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D000497:Alloys; D008345:Manganese; D014001:Tin; D009532:Nickel