标题： 中子磁散射中的尺度问题 显示英文标题

标题： Scaling in Magnetic Neutron Scattering

摘要： 我们报道了在块体铁磁材料的介观磁性微结构中发现尺度行为的结果。在解析微观磁性理论的支持下，我们引入了场相关的尺度长度$l_{\mathrm{C}}(H)$，它通过磁弹性和磁晶各向异性描述由微观结构缺陷引起的特征长波长磁化涨落。尺度长度$l_{\mathrm{C}}$被确认由场相关的交换长度$l_{\mathrm{H}}$（取决于磁相互作用）和一个场无关的贡献组成，该贡献反映了磁各向异性场和磁静力涨落的性质。后一发现根植于晶粒微观结构与微观磁响应函数之间的卷积关系。我们通过分析磁中子散射截面的实验数据验证了这一尺度属性。当以无量纲尺度散射矢量$\mathfrak{q}(H) = q \, l_{\mathrm{C}}(H)$为函数绘制时，纳米晶 Co 和基于 Nd-Fe-B 的纳米复合材料的场相关振幅尺度中子数据坍塌到单一主曲线，展示了普遍行为。尺度长度$l_{\mathrm{C}}$提供了一个框架来分析场相关的中子散射截面，突出了决定磁性材料介观微观结构的关键长度尺度的存在。 显示英文摘要

摘要： We report the discovery of scaling in the mesoscale magnetic microstructure of bulk ferromagnets. Supported by analytical micromagnetic theory, we introduce the field-dependent scaling length $l_{\mathrm{C}}(H)$, which describes the characteristic long-wavelength magnetization fluctuations that are caused by microstructural defects by means of magnetoelastic and magnetocrystalline anisotropy. The scaling length $l_{\mathrm{C}}$ is identified to consist of the micromagnetic exchange length of the field $l_{\mathrm{H}}$, which depends on the magnetic interactions, and a field-independent contribution that reflects the properties of the magnetic anisotropy field and the magnetostatic fluctuations. The latter finding is rooted in the convolution relationship between the grain microstructure and micromagnetic response functions. We validated the scaling property by analyzing experimental data for the magnetic neutron scattering cross section. When plotted as a function of the dimensionless scaled scattering vector $\mathfrak{q}(H) = q \, l_{\mathrm{C}}(H)$, the field-dependent amplitude-scaled neutron data of nanocrystalline Co and a Nd-Fe-B-based nanocomposite collapse onto a single master curve, demonstrating universal behavior. The scaling length $l_{\mathrm{C}}$ provides a framework for analyzing the field-dependent neutron scattering cross section, highlighting the existence of critical length scales that govern the mesoscale microstructure of magnetic materials.