原位磁化X射线粉末衍射法测还原铁粉的微观磁致伸缩系数

Magnetostriction Coefficient of Reduction Iron Powder Measured by In-situ Magnetization X-ray Diffraction Methed

首次报导X射线粉末衍射法测量铁粉晶胞的磁致伸缩系数。还原铁粉样品原位磁化后 ,铁立方晶胞产生磁致伸缩效应 ,晶胞参数的变化引起衍射峰位置和晶面间距的变化。实验测得铁晶胞λ1 0 0 为 3 .3 3× 10 - 4,此结果表明铁晶胞的微观磁致伸缩系数比棒状、薄膜或粉末压片的系数大约 16倍。对此现象进行了合理的理论解释 ,指出大块材料中的粉末多晶之间具有较大的空隙 。

In situ magnetization X-ray powder diffraction method is firstly applied to measure magnetostriction coefficient of reduction iron powder. When magnetified, changes of crystal cell parameters result in correspondently the changes of diffraction peaks positions and Bragg d-spacing. It is measured that λ_(100)=3.33×10^(-4) of iron crystal cell is 16 times as that of bulk iron. The difference of λ_(100) between microscopic cell and bulk iron can be theoretically explained. Because there are large free space between powder crystals in bulk iron sample, the magnetostriction coefficient of bulk iron is much smaller than that of iron crystal cell.