<正> 本工作试图通过对Nd_2Fe_(14)B相的Mossbauer效应研究,进一步认识四方结构中六个不同Fe位的微观性质,进而得出Fe原子在不同晶位的布居与宏观磁性能间的定性联系。 一、实验 合金是由99.9％Nd,99.99％的电解Fe和硼铁制备的,成分为Nd_xB_yFe_(100-x-y),x=15,16,y=0,4.3,5.3,7,7.4,10.5。由中频真空感应炉熔炼,浇成2kg的铸锭。将合金锭在甲苯中破碎,然后在球磨机中研磨成细粉,过100mesh的筛网,将粉在磁场下预取向,并在与磁场平行的方向上加(0.4—0.7)kPa的压力。在Ar气保护下于
The permanent magnets of the nominal composition Nd_xB_yFe(100-x-y) with x=15 or 16 and y=4-10 were investigated by means of Mossbauer effect. The Mossbauer spectra may be resolved into the subspectra corresponding to the different phases. Mossbauer measurements show that the constituent phases of the alloy are varied with its B content. The α-Fe and Nd_2Fe_(17) are observed in the alloy without B; the tetragonal Nd_2Fe_(14)B occurs and Nd_2Fe_(17) disappears in that containing 4 at.-%B; the Nd-rich and B-rich phases in addition to Nd_2Fe_(14)B exist and α-Fe vanishes in that up to 7 at.-%B and the B-rich phase tends to increase predominantly while further increasing the B content. Six subspectra of the tetragonal phase correspond to the six non-equivalent Fe sites. It is pointed Out that j_2 site posseses maximum hyperfine field and also maximum quadruple splitting. The preferential occupation of j_2 site by Fe atoms is critical for establishing the high anisotropy and remanence.
参考文献
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| [4] | Herbst, J. F. |
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