Inverse magnetocaloric effect in ferromagnetic Ni-Mn-Sn alloys

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Krenke T., Duman E., Acet M., Wassermann E., Moya X., Manosa L., ...Daha Fazla

NATURE MATERIALS, cilt.4, sa.6, ss.450-454, 2005 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 4 Sayı: 6
  • Basım Tarihi: 2005
  • Doi Numarası: 10.1038/nmat1395
  • Dergi Adı: NATURE MATERIALS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.450-454
  • Ankara Üniversitesi Adresli: Hayır

Özet

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(1-3). 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(4,5). 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.