Fe/V多层膜中亚稳结构Fe的形成及其磁学性能

采用电子束蒸镀的方法,通过改变多层膜的周期结构,成功地制备出具有不同晶格常数的bcc亚稳结构铁相的Fe/V多层膜,并研究了亚稳结构铁相形成对其磁性影响的规律.实验结果表明,多层膜中Fe与V层均由纳米晶粒组成.Fe层厚度小于2nm时,受多层膜界面自由能作用,Fe与V相互准外延生长,多层膜由点阵常数一致的体心立方相组成,其点阵常数随样品V/Fe层厚度比的增大而增加.多层膜平均原子磁矩随铁或钒层厚度的改变发生明显变化:当钒层厚度固定为6nm时,铁原子磁矩随铁层厚度的增加逐渐下降,在2nm处出现极小值后又随铁层增厚而回升;对于铁层厚度固定为1.6nm的样品,磁矩在钒层厚度为3nm时出现极大值.

Formation of Metastable Structured Fe in Fe/V Multilayers and its Magnetic Properties

Metastable bcc Fe phases with various lattice constants were obtained in Fe/V multilayers by controlling their periodicities and alternate electronic beam vapor deposition.The formation of metastable Fe and its influence on magnetic properties were investigated in this study.Experimental results indicate that both Fe and V layers in the films consist of bcc polycrystalline with nanometer grain size.When Fe layer thickness(t_(Fe)) was below 2nm,Fe and V layers epitaxial-like grew each other due to the action of interface free energy,and a uniting bcc structure was formed in the multilayers.The lattice parameter of bcc phase increased with increasing ratio of t_V/t_(Fe).The atomic magnetic moment evolved remarkably with t_(Fe) and t_V,i.e.,for the Fe/V(6nm) multilayers,the average atomic magnetic moment got a minimum value at t_(Fe)=2nm,and it decreased with t_(Fe) when t_(Fe) was thinner 2nm and increased again for t_(Fe) thicker than 2nm. For the multilayers with t_(Fe)=(1.6)nm,the atomic magnetic moment reached a maximum value for t_V=3nm.