EFFECTS OF GRAIN-SIZE DISTRIBUTION ON EFFECTIVE ANISOTROPY AND COERCIVITY FOR NANOCRYSTALLINE HARD MAGNETIC MATERIAL
Eeffects Of Grain—Size Distribution On Effective Anisotropy And Coercivity For Nanocrystalline Hard Magnetic Material

Taking nanocrystalline Nd2Fe14B as a typical sample, the effects of grain-size distribution on the anisotropy and coercivity in nanocrystalline hard magnetic materials have been investigated. The calculating results reveal that the effective anisotropy and coercivity of material decrease with the reduction of grain size, and rapidly decrease while the grain size is less than 20 nm. The non-ideal distribution of grain size does not change the variation trendency of the effective anisotropy and coercivity with reducing grain size, however, promotes the decrease rate of effective anisotropy and coercivity. When the microstructure factor pc=0.7, our calculated results agree basically with the experimental results. The decrement of coercivity is mainly due to the reduction of effective anisotropy for nanocrystalline Nd2Fe14B hard magnetic material.