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Title: Calculations of the magnetic entropy change in amorphous through a microscopic anisotropic model: Applications to Dy{sub 70}Zr{sub 30} and DyCo{sub 3.4} alloys

We report theoretical investigations on the magnetocaloric effect, described by the magnetic entropy change in rare earth—transition metal amorphous systems. The model includes the local anisotropy on the rare earth ions in Harris-Plischke-Zuckermann assumptions. The transition metals ions are treated in terms of itinerant electron ferromagnetism and the magnetic moment of rare earth ions is coupled to the polarized d-band by a local exchange interaction. The magnetocaloric effect was calculated in DyCo{sub 3.4} system, which presents amorphous sperimagnetic configuration. The calculations predict higher refrigerant capacity in the amorphous DyCo{sub 3.4} than in DyCo{sub 2} crystal, highlighting the importance of amorphous magnetocaloric materials. Our calculation of the magnetocaloric effect in Dy{sub 70}Zr{sub 30}, which presents amorphous asperomagnetic configuration, is in good agreement with the experimental result. Furthermore, magnetic entropy changes associated with crystal-amorphous configurations change are estimated.
Authors:
; ; ; ; ; ;  [1] ;  [2] ;  [3] ;  [4] ;
  1. Instituto de Física, Universidade do Estado do Rio de Janeiro—UERJ, Rua São Francisco Xavier, 524, 20550-013 Rio de Janeiro (Brazil)
  2. Sociedade Unificada de Ensino Superior e Cultura, SUESC, 20211-351 Rio de Janeiro (Brazil)
  3. Instituto de Aplicação Fernando Rodrigues da Silveira, Universidade do Estado do Rio de Janeiro, Rua Santa Alexandrina, 288, 20260-232 Rio de Janeiro (Brazil)
  4. Laboratório Nacional de Luz Sincroton—LNLS, 13083-970 Campinas, São Paulo (Brazil)
Publication Date:
OSTI Identifier:
22305794
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 14; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AMORPHOUS STATE; ANISOTROPY; BINARY ALLOY SYSTEMS; COBALT ALLOYS; COMPUTERIZED SIMULATION; CONFIGURATION; CRYSTALS; DYSPROSIUM ALLOYS; ELECTRONS; ENTROPY; EXCHANGE INTERACTIONS; FERROMAGNETISM; IONS; MAGNETIC MOMENTS; MAGNETIC PROPERTIES; RARE EARTHS; TRANSITION ELEMENTS; ZIRCONIUM ALLOYS