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科学的新发展常常以技术的进步为先导.正是由于薄膜技术的高度发展,人们可以逐个原子层地制备薄膜和控制薄膜的生长,从而激发起科学家们去研究人造超晶格的结构.所谓超晶格是指几种不同材料按一定厚度作周期性交替生长的多层薄膜结构。 一、历史概况 超晶格的研究首先是从半导体材料开始的(譬如 GaAs/AlAs).近年来对非晶态半导体也作过超晶格研究,如1983年美国EXXON公司的B.Abeles和 T.Tiedje[1]介绍的非晶 a-Si:H/a-SiNx:H等.近年来人们对金属超晶格进行了研究[2].过去,人们也曾无意识地研究过金属多层膜问题,如早期从X射线角度研… 相似文献
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MAGNETIC PROPERTIES AND CRYSTALLIZATION OF THE RAPIDLY QUENCHED (Fe1-xNdx) 81.5B18.5 ALLOYS 总被引:1,自引:0,他引:1 下载免费PDF全文
Magnetic properties and crystallization behaviors of amorphous (Fe1-xNdx) 81.5B18.5 alloys were studied. The crystallization temperature is found to rise at first and then drop monotonically with x, having a maximum value of 976K at x=0.11 (9at% Nd). The (Fe1-xNdx) 81.5B18.5 alloys prepared at a quenching rate of vs = 6.6m /s are amorphous, and exhibit good glass formability. Both the coercive field Hc and energy product (BH)max depend strongly on Nd concentration. Amorphous (Fe1-xNdx) 81.5B18.5 alloys with higher Nd concentration have a high coercive field at low temperature, due to the large random uniaxial anisotropy of Nd. The room-temperature Hc and (BH)max obtained on optimal annealing con-ditions show two maxima as a function of Nd concentration x. The highest room-temperature coercive field Hc =22 kOe within the Nd concentrations around x=0.368 and the maximum energy product(RH)max= 13.3 MG·Oe at x =0.055 are observed. The hard magnetic properties of these crystallized samples are related to the presence of the bard magnetic Nd2Fe14B phase. 相似文献
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