论文标题
通过磁性中子散射解决纳米颗粒中的复杂自旋纹理
Resolving complex spin textures in nanoparticles by magnetic neutron scattering
论文作者
论文摘要
为了想象成像三维磁化结构，我们表明磁性小角度中子散射（SANS）的技术对纳米颗粒的内部自旋结构的细节高度敏感。通过将SAN与数值微磁性计算相结合，我们研究了纳米颗粒中从单域到多域行为的过渡及其对随后的磁性SANS横截面的影响。在关键的单域大小上方，我们发现横截面和相关的相关函数不能再用均匀的粒子模型来描述，例如在与著名的吉尼法律的偏差中。我们确定了出现在避孕时出现涡流样旋转结构的明确签名。磁性磁体的微磁方法具有未来研究的巨大潜力，因为它为纳米颗粒的中尺度磁化特征提供了基本见解。
In the quest to image the three-dimensional magnetization structure we show that the technique of magnetic small-angle neutron scattering (SANS) is highly sensitive to the details of the internal spin structure of nanoparticles. By combining SANS with numerical micromagnetic computations we study the transition from single-domain to multi-domain behavior in nanoparticles and its implications for the ensuing magnetic SANS cross section. Above the critical single-domain size we find that the cross section and the related correlation function cannot be described anymore with the uniform particle model, resulting e.g. in deviations from the well-known Guinier law. We identify a clear signature for the occurrence of a vortex-like spin structure at remanence. The micromagnetic approach to magnetic SANS bears great potential for future investigations, since it provides fundamental insights into the mesoscale magnetization profile of nanoparticles.
