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Computer simulation of the effect of an ultra soft phase on the magnetic properties of nanocrystalline permanent magnets
- Source :
- Journal of Magnetism and Magnetic Materials. 234:331-352
- Publication Year :
- 2001
- Publisher :
- Elsevier BV, 2001.
-
Abstract
- Micromagnetic models of assemblies of randomly oriented, exchange coupled, nanocrystals consisting of a magnetically hard uniaxial phase (typified by Nd 2 Fe 14 B) together with an ultra-soft phase (typified by α -iron) have been studied numerically. The hard crystallites were located on a three dimensional cubic lattice, and cubic crystallites of the soft phase were inserted at the junctions of every group of eight hard crystallites. Demagnetizing curves were obtained as a sequence of static equilibrium states in an incrementally changing applied field. Values of the coercivity, remanence and energy product are reported as functions of Δ GH , the grain size of the hard phase, and of ϕ S , the fractional volume of the soft phase. The dependence on Δ GH falls quite rapidly with increasing ϕ S . The low anisotropy and high saturation magnetization of the α -iron make approximately equal contributions to remanence enhancement in the model. Its remanence values are in quite good agreement with experimental values for Nd 2 Fe 14 B containing α -iron. However, its values for the coercivity and energy product, though decidedly lower than those obtained computationally by some other authors, significantly exceed those obtained experimentally, but show a similar variation with Δ GH and ϕ S .
Details
- ISSN :
- 03048853
- Volume :
- 234
- Database :
- OpenAIRE
- Journal :
- Journal of Magnetism and Magnetic Materials
- Accession number :
- edsair.doi...........8f137a0ef66ba14f816f9fa09e702a71