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Zirconium nitride powders with rock salt structure (γ-ZrNx) are prepared by mechanical milling of a mixture of Zirconium and hexagonal boron nitride (h-BN) powders. The products are analysed by x-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy (ITS). The formation mechanism of γ-ZrNx by ball milling technique is investigated in detail. N atoms diffuse from amorphous BN (a-BN) into Zr to form Zr(N) solid solution alloy, then the Zr(N) solid solution alloy decomposes into γf-ZrNx. No ZrB2 is observed in the as-milled samples or the samples annealed at 1050° C for 2h. 相似文献
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In this paper magnetization remanence curves were studied for nanocrystalline Pr8Fe87B5, Pr12Fe82B6 and Pr15Fe77B8. Initially the sample was at remanence following saturation along z-axis. After rotating the magnet by 5n degrees (n=0, 1, ..., 18) a field H was applied along z-axis and then decreased to zero, and the remanence Jr^n was measured as a function of H. The curves were compared with those calculated based on the nucleation of reverse domain model and domain wall pinning model. The latter model succeeds in simulation much better than the former, and it is concluded that the magnetization reversal is dominated by domain wall pinning for all the samples. The nucleation mechanism contribution, while remains small, increases with the increase of Pr content. 相似文献
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The magnetization curves along the crystal axes for Gd_2Fe_{17} and Gd_2Fe_{17}H_3 were analysed based on the single-ion model. If the Gd-Fe exchange interaction has been taken as isotropic as usual, the fitted values of magneto-crystalline anisotropy of the Fe sublattices in Gd_2Fe_{17} and Gd_2Fe_{17}H_3 would become unreasonably different from those of the corresponding Y or Lu compounds. It was shown that the large difference is caused by the neglect of the anisotropy of the Gd-Fe exchange interaction. 相似文献
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Magnetization and demagnetization behaviours of melt-spun Pr12Fe82B6 and Pr8Fe87B5 ribbons 下载免费PDF全文
Nanocrystalline Pr_{12}Fe_{82}B_6 and nanocomposite Pr_8Fe_{87}B_5 ribbons have been prepared using a melt spinning technique. Recoil loops have been measured at 20, 200 and 300K. Demagnetization curves are analysed by dividing it into reversible and irreversible portions. High recoil loop susceptibility at low applied field and large reversible change in the demagnetization curve have been found in Pr_8Fe_{87}B_5 ribbons, showing that the reversible behaviours in nanocomposite permanent magnets originate primarily from the magnetically soft phase. The hysteresis in recoil loops found in Pr_8Fe_{87}B_5 ribbons originates from the soft phase α-Fe that suffers a stress. 相似文献
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