Urbaniak Maciej, Holzinger Dennis, Ehresmann Arno, Stobiecki Feliks
Institute of Molecular Physics, Polish Academy of Sciences, ul. M. Smoluchowskiego 17, 60-179 Poznań, Poland.
Department of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany.
Biomicrofluidics. 2018 Aug 20;12(4):044117. doi: 10.1063/1.5034516. eCollection 2018 Jul.
Colloidal magnetophoretic lensing of water suspended micrometer-sized superparamagnetic beads (SPBs) above a topographically patterned magnetic thin film system with perpendicular magnetic anisotropy is demonstrated. The magnetic pattern consisting of concentric annuli of micron-sized widths has been superimposed with a rotating external magnetic field, and it is shown that the trajectories of the SPBs above this structure are similar to light rays in an optical focusing lens. SPB trajectories converge towards the central region and have divergent trajectories while passing the center. The experimental findings are corroborated by a quantitative model for the SPB trajectories. The magnetophoretic lensing effect leads to a high SPB concentration in the center of the pattern and may be useful for applications where SPBs have to approach each other in a controlled way.
本文展示了在具有垂直磁各向异性的地形图案化磁性薄膜系统上方，对水悬浮的微米级超顺磁珠（SPB）进行胶体磁泳透镜效应的实验。由微米级宽度的同心环组成的磁性图案与旋转的外部磁场叠加，结果表明，该结构上方SPB的轨迹类似于光学聚焦透镜中的光线。SPB轨迹向中心区域汇聚，并在通过中心时具有发散轨迹。SPB轨迹的定量模型证实了实验结果。磁泳透镜效应导致图案中心的SPB浓度很高，这对于需要以可控方式使SPB相互靠近的应用可能很有用。
