Magnetic Alignment of Magnetically Blaxial Diamagnetic Rods Under Rotating Magnetic Fields
Magnetic Alignment of Magnetically Blaxial Diamagnetic Rods Under Rotating Magnetic Fields
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旋转磁场下磁双轴反磁棒的磁对准
DOI：
10.1143/jjap.51.057301
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
S. Tsukui and T. Kimura
中科院分区：
文献类型：
--
作者：
T. Kimura;G. Song;K. Matsumoto;K. Fujita;and F. Kimura;S. Tsukui and T. Kimura
研究了磁性双轴抗磁棒在旋转磁场作用下的定向行为，阐明了粒子形状和转速对定向方式的影响。制备了三种类型的棒（约1.1 mmφ× 3 mm）：(i)棒轴平行于χ 1，（ii）平行于χ 2， （iii）平行于χ 3，其中χs为抗磁化率张量的主轴和χ 1> χ 2> χ 3。在视频中记录杆的运动，并测量与仿真比较所需的角度。通过数值求解包含磁力矩和流体动力力矩的转矩方程进行仿真。实验结果与仿真结果吻合较好。结果表明，在大多数实验条件下，棒状样品（ii）的χ 3轴不平行于旋转磁场轴；这与磁性单轴粒子（χ 1= χ 2> χ 3）的情况形成鲜明对比，其中χ 3轴与粒子形状和/或旋转速度无关。这一观察结果可以用磁能和取向动力学来解释。
The alignment behavior of magnetically biaxial diamagnetic rods under rotating magnetic fields is studied to elucidate the effects of particle shape and rotation speed on alignment manner. Three types of rod (ca. 1.1 mmφ× 3 mm) are prepared:(i) rod axes parallel to χ 1,(ii) parallel to χ 2, and (iii) parallel to χ 3, where χs are the principal axes of the diamagnetic susceptibility tensor and χ 1> χ 2> χ 3. The motion of the rod is recorded on video and the angles required for the comparison with simulation are measured. Simulation is performed by numerically solving a torque equation including magnetic and hydrodynamic torques. The experimental results show a good agreement with simulation results. It is shown that the χ 3-axis of rod sample (ii) does not align parallel to the axis of the rotating magnetic field under most experimental conditions; this is in marked contrast to the case with magnetically uniaxial particles (χ 1= χ 2> χ 3), for which the χ 3-axis aligns irrespective of particle shape and/or rotation speed. This observation is interpreted in terms of magnetic energy and orientation kinetics.