Quasicoherent nucleation mode in two-phase nanomagnets

Ralph Skomski, J. P. Liu, David J Sellmyer

Research output: Contribution to journalArticle

61 Citations (Scopus)

Abstract

Magnetization processes in advanced magnetic nanostructures are investigated. For the case of spherical soft or semihard grains surrounded by a very hard matrix a bulging nucleation mode is discovered. The bulging mode exhibits the radial angular symmetry of the coherent mode, but it is incoherent due to its radial variation. The radial dependence of the bulging mode is obtained by solving a spherical Bessel equation which is subject to appropriate boundary conditions. In contrast to the coherent mode, the bulging mode yields a nucleation-field coercivity which depends on the exchange stiffness and on the size of the grain. There is a critical grain radius 7.869√A/μ0M2s above which the bulging mode is replaced by a modified curling mode. The nucleation modes realized in nanostructures affect the demagnetizing-field corrections necessary to account for the external shape of magnetic samples. Since strong but short-range exchange and weak but long-range magnetostatic interactions compete on nanostructural length scales, the sample-shape dependence of the hysteresis loops cannot be mapped onto a purely magnetostatic demagnetizing factor.

Original languageEnglish (US)
Pages (from-to)7359-7365
Number of pages7
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume60
Issue number10
DOIs
StatePublished - Jan 1 1999

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Nucleation
Magnetostatics
bulging
nucleation
Nanostructures
Hysteresis loops
Coercive force
Magnetization
Stiffness
Boundary conditions
magnetostatics
coercivity
stiffness
hysteresis
boundary conditions
magnetization
radii
symmetry
matrices
interactions

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Quasicoherent nucleation mode in two-phase nanomagnets. / Skomski, Ralph; Liu, J. P.; Sellmyer, David J.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 60, No. 10, 01.01.1999, p. 7359-7365.

Research output: Contribution to journalArticle

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