Nucleus Size Determination for Nd₂Fe₁₄B, Sm₂Co₁₇, SmCo₅ and BaFe₁₂O₁₉ Magnets

Abstract:

The nucleus size was determined for the following phases: Nd₂Fe₁₄B, Sm₂Co₁₇, SmCo₅ and BaFe₁₂O₁₉. These phases are the basis for the most relevant sintered permanent magnets. For the determination, it was assumed a spherical grain, and that the reversal of magnetization occurs in a tiny shell near the surface. The Magnetostatic energy for each domain configuration was found by means of Legendre polynomials. The nucleus is a spherical cap, near the equator. After reaching the nucleus critical size, the reversal of magnetization continues spontaneously, reducing the global energy of the system. It was found that, for each grain size, there is a different nucleus size.

• Periodical: Materials Science Forum (Volumes 727-728)
• Pages: 151-156
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.727-728.151
• Online since: August 2012
• Authors: Marcos Flavio de Campos, José Adilson de Castro
• Keywords: Coercivity, Grain Size, Magnetostatic Energy

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