Inter-grain exchange interaction for single-phase nanocrystalline Nd-Fe-B magnets

The demagnetization curve as a function of intensity of the inter-grain exc hange interaction was calculated for single-phase nanocrystalline Nd-Fe-B m agnets by use of the finite-element technique of micromagnetics. Also, the strength of the exchange interaction was estimated as a function of the N-d content x for the nanocrystalline NdxFe94-xB6 magnets by comparing the abo ve result with the experimental relation between H-i(c) and x for the magne ts. We found that the inter-grain exchange interaction decreases with the i ncrease of x, are approximate to 70% and approximate to 60% of the inter-gr ain exchange interaction for x=15.5(mu H-0 i(c) approximate to2.0T) and x=1 9(mu H-0i(c) approximate to2.3T), respectively.