Temperature- and field-induced entropy changes in nanomagnets

Ralph Skomski, Christian Binek, T. Mukherjee, S. Sahoo, D. J. Sellmyer

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Room-temperature magnetic-entropy changes in nanostructures for magnetic refrigeration are investigated by model calculations. Using a mean-field approach, the magnetic entropy is calculated as a function of temperature, magnetic field, particle size, anisotropy, and interaction strength. Both isotropic (Heisenberg) and uniaxial (Ising and XY) anisotropies are considered. The nanoparticle entropy strongly depends on the character of the anisotropy, in contrast to atomic ferromagnetism, where the anisotropy energy is much smaller than the interaction energy. Most promising are isotropic particles and particles with weak easy axis anisotropy, as well as easy-plane particle with the field in the plane. The optimum nanoparticle size is not much larger than 1 nm, because the relative magnetization direction in a nanoparticle is usually frozen and do not contribute to the entropy change.

Original languageEnglish (US)
Article number07B329
JournalJournal of Applied Physics
Volume103
Issue number7
DOIs
StatePublished - 2008

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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