Maranville Brian B, Kirby Brian J, Grutter Alexander J, Kienzle Paul A, Majkrzak Charles F, Liu Yaohua, Dennis Cindi L
NIST Center for Neutron Research, 100 Bureau Drive, Gaithersburg, MD 20899, USA.
Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
J Appl Crystallogr. 2016 Jun 9;49(Pt 4):1121-1129. doi: 10.1107/S1600576716007135. eCollection 2016 Aug 1.
The presence of a large applied magnetic field removes the degeneracy of the vacuum energy states for spin-up and spin-down neutrons. For polarized neutron reflectometry, this must be included in the reference potential energy of the Schrödinger equation that is used to calculate the expected scattering from a magnetic layered structure. For samples with magnetization that is purely parallel or antiparallel to the applied field which defines the quantization axis, there is no mixing of the spin states (no spin-flip scattering) and so this additional potential is constant throughout the scattering region. When there is non-collinear magnetization in the sample, however, there will be significant scattering from one spin state into the other, and the reference potentials will differ between the incoming and outgoing wavefunctions, changing the angle and intensities of the scattering. The theory of the scattering and recommended experimental practices for this type of measurement are presented, as well as an example measurement.
外加强磁场的存在消除了自旋向上和自旋向下中子的真空能态简并性。对于极化中子反射测量，这必须包含在用于计算磁性层状结构预期散射的薛定谔方程的参考势能中。对于磁化方向与定义量子化轴的外加磁场完全平行或反平行的样品，自旋态之间没有混合（无自旋翻转散射），因此这种附加势能在整个散射区域是恒定的。然而，当样品中存在非共线磁化时，会有显著的从一种自旋态到另一种自旋态的散射，并且参考势能在入射波函数和出射波函数之间会有所不同，从而改变散射角和强度。本文介绍了这种类型测量的散射理论和推荐的实验方法，以及一个示例测量。
