Magnetic manipulation of micro- and nanoscale objects like nanoparticles, nanotubes, and nanowires are attracting much attention due to the potential applications in biosensing, electronics, spintronics, optoelectronics, sensors, and thermoelectric devices. As a facile assembling technique with advantages including easily implementing, non-intrusive, no chemical interaction and magnetic strength degrade, a deep understanding of the formation of the materials made by magnetic manipulation becomes significant. In terms of optimization and cost-effectiveness, the numerical method is the preferable approach for investigating the phenomenon of the constitution of magnetic micro/nano materials under the magnetic manipulation process as the numerical simulations offer the flexibility, feasibility, simplicity, and freedom to try variety parameters of physical problems. This research reports the study of the manipulation of nanoscale nickel (Ni) wires under a uniform magnetic field using the Monte Carlo method (MC). The MC method is known as the method of statistical trials which solves problems using sequences of random numbers. The MC method is also widely applied in variety physical systems for some problems with many degrees of freedom which are computationally intractable.

In this research, the alignment of Ni nanowires under the effect of different magnetic fields and dipole-dipole interaction between wires was studied. The nanowires were treated as the wires with a uniform square cross-section with a magnetic dipole along the wire. The calculated value of volume fraction range of one batch nanowires in a 15 ml ethanol solution is around 0.072 to 0.08. The distribution of clusters of nanowires was presented in this study. Different applied magnetic fields were applied to the numerical simulation for the cluster distribution analysis. The external applied magnetic field strength is from 250 to 2000 Gauss (Gs). It was found that a small applied magnetic field strength can align the Ni nanowire well along with the magnetic direction efficiently. The big applied magnetic field strength, of course, can also achieve the goal for the nanowires conforming to the magnetic direction. However, it causes more nanowires aggregate together to form larger clusters and limits the distribution of nanowires during the magnetic manipulation processes. In addition, it was also found the dipole-dipole interaction has more significant influences on the formation of the clusters compared with the applied magnetic field. To validate the simulation results, Ni nanowires synthesized by using an electrodeposition method in nanoporous polycarbonate (PC) templates were fabricated and the assembly of the nanowires under the magnetic field was compared with experimental results.


Simulation of Large-Scale Magnetic Manipulation of Micro/Nano-Material Based on Monte Carlo Method

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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