Polarisation optimisation for ferromagnetic diffraction : A case study of iron
Polarisation optimisation for ferromagnetic diffraction : A case study of iron
复制标题
铁磁衍射的偏振优化：铁的案例研究
DOI：
10.1016/j.nima.2006.07.033
复制
发表时间：
2006
影响因子：
1.4
通讯作者：
M. Cooper
中科院分区：
文献类型：
--
作者：
L. Bouchenoire;Simon D. Brown;P. Thompson;C. Detlefs;M. Cooper
通过用位相延迟器控制入射光束的偏振，可以在非共振X射线衍射实验中测量铁磁体的磁效应。然而，结果很大程度上依赖于轨道起伏引起的寄生极化。我们发现，通过在金刚石位相板前插入布拉格角接近45°的Si(333)沟道切割偏振器，大部分不需要的偏振被拒绝，磁效应得到增强。我们以铁为例，演示了该实验组态在非共振铁磁衍射中的性能。将沟道切割晶体与相位板相结合，使铁磁铁对(220)面反射的磁荷散射比提高到原来的三倍。此外，通过将相位延迟器的ψ角设置为11°而不是45°，磁效应的测量受到发生在钻石相板中的多次反射的影响较小。
The magnetic effect from a ferromagnet can be measured in a non-resonant X-ray diffraction experiment by controlling the polarisation of the incident beam with a phase retarder. However, the results strongly depend on the parasitic polarisation caused by fluctuations of the orbit. We found that by inserting a Si (333) channel-cut polariser with a Bragg angle close to 45° in front of the diamond phase-plate, most of the unwanted polarisation was rejected and the magnetic effect was enhanced. We demonstrate the performance of this experimental configuration for non-resonant ferromagnetic diffraction with the example of iron. The ratio of magnetic to charge scattering from ferromagnetic iron was increased up to three times for the (220) reflection of Fe by combining the channel-cut crystal and the phase-plate. Also, by setting the ψ angle of the phase retarder to 11° rather than 45°, the measurements of the magnetic effect were less affected by the presence of multiple reflections occurring in the diamond phase-plate.