The Critical Volume for Nucleation

Marcos Flavio de Campos; José Adilson de Castro

doi:10.4028/www.scientific.net/MSF.660-661.279

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HomeMaterials Science ForumMaterials Science Forum Vols. 660-661The Critical Volume for Nucleation

The Critical Volume for Nucleation

Abstract:

In magnets based in phases with high magnetocrystalline anisotropy like Nd2Fe14B or SmCo5 there is a competition between magnetostatic energy and domain wall energies. If the grain size is large, the formation of domain walls is energetically favorable. When the formation of domain walls is an unfavorable process, coercivity is larger. A better comprehension of this phenomenon is possible if the energy necessary for the first domain wall formation is properly evaluated. To address this problem, the magnetostatic energy of a sphere magnetized in two opposite directions, separated by a domain wall, is calculated using Legendre Polynomials. The data allow the determination of the reversible volume for nucleation. It is predicted a “recoil effect”, the magnetization may be reversible until a given volume of reverse magnetization.

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Materials Science Forum (Volumes 660-661)

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279-283

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https://doi.org/10.4028/www.scientific.net/MSF.660-661.279

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October 2010

Authors:

Marcos Flavio de Campos, José Adilson de Castro

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Coercivity, Grain Size, Magnetostatic Energy

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