Experimentalphysik, Universität des Saarlandes, Postfach 151150, Geb. D2 2, D-66041 Saarbrücken, Germany.
Nanoscale. 2015 Oct 28;7(40):17122-30. doi: 10.1039/c5nr04243g. Epub 2015 Oct 1.
The response of a colloidal dispersion of Ni nanorods to an oscillating magnetic field was characterized by optical transmission measurements as well as small-angle neutron scattering (SANS) experiments using the TISANE (Time-dependent SANS experiments) technique. Exposed to a static magnetic field, the scattering intensity of the rod ensemble could be well described by the cylinder form factor using the geometrical particle parameters (length, diameter, orientation distribution) determined by transmission electronmicroscopy and magnetometry. An oscillation of the field vector resulted in a reorientation of the nanorods and a time-dependency of the scattering intensity due to the shape anisotropy of the rods. Analysis of the SANS data revealed that in the range of low frequencies the orientation distribution of the rods is comparable to the static case. With increasing frequency, the rod oscillation was gradually damped due to an increase of the viscous drag. It could be shown that despite of the increased friction in the high frequency range no observable change of the orientation distribution of the ensemble with respect to its symmetry axis occurs.
通过光传输测量以及使用 TISANE（时间相关小角中子散射实验）技术的小角中子散射（SANS）实验，研究了纳米棒胶体分散体对振荡磁场的响应。在静态磁场作用下，棒系的散射强度可以用圆柱形态因子很好地描述，使用透射电子显微镜和磁强计确定的几何粒子参数（长度、直径、取向分布）来描述。磁场矢量的振荡导致纳米棒的重新取向，以及由于棒的形状各向异性导致散射强度的时间依赖性。对 SANS 数据的分析表明，在低频范围内，棒的取向分布与静态情况相当。随着频率的增加，由于粘性阻力的增加，棒的振荡逐渐被阻尼。可以表明，尽管在高频范围内摩擦力增加，但棒系相对于其对称轴的取向分布没有观察到变化。
