| Autor: |
N D The, N Q Hoa, S K Oh, S C Yu, H D Anh, L V Vu, N Chau |
| Předmět: |
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| Zdroj: |
Journal of Physics D: Applied Physics; Jan2007, Vol. 40 Issue 1, p119-122, 4p |
| Abstrakt: |
Nanocomposite hard magnetic materials (Nd,Dy)4.5Fe77.5B18(No. 1) and (Nd,Dy)4.5Fe76B18Nb1.2Cu0.3(No. 2) have been prepared by crystallizing amorphous ribbons, fabricated by single roll melt-spinning. The evolution of a multiphase structure was monitored by an x-ray diffractometer and by thermomagnetic measurement. We observed that, at annealing temperatures below 670?°C, there is crystallization of soft phase Fe3B and a small amount of hard phase Nd2Fe14B. At annealing temperatures above 670?°C, crystallization of ?-Fe and probably Dy2Fe14B phases with large magnetocrystalline anisotropy led to a drastic enhancement in the hard magnetic properties of the materials. The maximum value of HCis found to be 4.2?kOe for sample No. 1. For sample No. 2, with co-doping of Nb and Cu, nanostructure refinement yields a strong enhancement in exchange coupling between the component phases. Thereby, we obtained high reduced-remanence of 0.78, high remanence of 1.15 and a high (BH)maxvalue up to 16.2?MGOe. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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