Gorkov Dmitry, Toperverg Boris P, Zabel Hartmut
II. Physikalisches Institut, Universität zu Köln, 50937 Köln, Germany.
Festkörperphysik/Experimentalphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany.
Nanomaterials (Basel). 2020 Apr 28;10(5):851. doi: 10.3390/nano10050851.
Traditionally, neutron scattering is an essential method for the analysis of spin structures and spin excitations in bulk materials. Over the last 30 years, polarized neutron scattering in terms of reflectometry has also contributed largely to the analysis of magnetic thin films and magnetic multilayers. More recently it has been shown that polarized neutron reflectivity is, in addition, a suitable tool for the study of thin films laterally patterned with magnetic stripes or islands. We provide a brief overview of the fundamental properties of polarized neutron reflectivity, considering different domain states, domain fluctuations, and different domain sizes with respect to the neutron coherence volume. The discussion is exemplified by a set of simulated reflectivities assuming either complete polarization and polarization analysis, or a reduced form of polarized neutron reflectivity without polarization analysis. Furthermore, we emphasize the importance of the neutron coherence volume for the interpretation of specular and off-specular intensity maps, in particular when studying laterally non-homogeneous magnetic films. Finally, experimental results, fits, and simulations are shown for specular and off-specular scattering from a magnetic film that has been lithographically patterned into a periodic stripe array. These experiments demonstrate the different and mutually complementary information that can be gained when orienting the stripe array parallel or perpendicular to the scattering plane.
传统上，中子散射是分析块状材料中自旋结构和自旋激发的重要方法。在过去30年里，基于反射测量的极化中子散射在磁性薄膜和磁性多层膜的分析中也发挥了很大作用。最近还表明，极化中子反射率还是研究具有磁条或磁岛横向图案化薄膜的合适工具。我们简要概述了极化中子反射率的基本特性，考虑了不同的畴态、畴涨落以及相对于中子相干体积的不同畴尺寸。通过一组模拟反射率来举例说明讨论内容，这些模拟反射率假设了完全极化和极化分析，或者是没有极化分析的简化形式的极化中子反射率。此外，我们强调中子相干体积对于解释镜面和非镜面强度图的重要性，特别是在研究横向非均匀磁性薄膜时。最后，展示了从光刻图案化为周期性条纹阵列的磁性薄膜的镜面和非镜面散射的实验结果、拟合和模拟。这些实验证明了将条纹阵列平行或垂直于散射平面取向时可以获得的不同且相互补充的信息。
