摘要
在X射线粉末衍射仪的样品台附近施加磁场 ,测得了在原位磁场下分别具有顺磁性、抗磁性、铁磁性、亚铁磁性、反铁磁性和磁性混合物的 6个样品的X射线衍射图谱 .与无磁场时的相应衍射图谱相比较 ,这些图谱中有衍射峰消失 ,又有新的衍射峰出现 ;或是峰位置和强度发生变化 ;而且磁场方向不同时 ,衍射图谱也不一样 .产生这些现象的部分原因可能是 ,在磁场下物质内部的磁矩沿着磁场方向定向 ,粉末晶胞内产生应力 ,导致晶格歧变 (如磁致伸缩效应 )
To obtain more crystal and magnetic structural information of powder crystals, magnetic field is introduced into X′Pert-MPD XRD apparatus with the strength of 0.42 T and two different directions: one direction of magnetic field is vertical to the sample holder and another is parallel. XRD patterns in situ magnetic field are obtained for six samples which are representative of paramagnetic, diamagnetic, ferromagnetic, ferrimagnetic, antiferromagnetic substances and reduction product of FeCl 2 by NaBH 4 respectively. Compared with XRD patterns obtained in the zero magnetic field, there are some diffraction peaks disappear, some occur, or some diffraction angles and counts change. In addition, the patterns are different under the different direction of magnetic field. The cause is that magnetic dipoles in crystals are oriented along with the direction of magnetic field. The oriented magnetic dipoles produce stress in crystals and make crystal lattice changed (such as magnetostriction) or even turn particles aligned along with the direction of magnetic field to form preferred orientation of particles.
基金
ProjectsupportedbytheNationalNaturalScienceFoundationofFujianporivcen
关键词
原位磁场
X射线粉末衍射
磁致伸缩
择优取向
in situ magnetic field, XRD, Magnetostriction, Preferred orientation
