Dynamics of magnetic nano-flake vortices in Newtonian fluids

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:419

Article

Bazazzadeh, Nasim¹  Mohseni, Seyed Majid¹  Khavasi, Amin²  Zibaii, Mohammad Ismail³  Movahed, S. M. S.¹  Jafari, G. R.¹ 

[1] Shahid Beheshti Univ, GC, Dept Phys, Tehran 19839, Iran

[2] Sharif Univ Technol, Dept Elect Engn, Tehran 115554363, Iran

[3] Shahid Beheshti Univ, GC, Laser & Plasma Res Inst, Tehran 19839, Iran

关键词: Brownian dynamics simulation;    Nano-flakes;    Magnetic vortex;    Nano-bio-magnetics;   

DOI  :  10.1016/j.jmmm.2016.06.066

来源: Elsevier

【 摘 要 】

We study the rotational motion of nano-flake ferromagnetic disks suspended in a Newtonian fluid, as a potential material owing the vortex-like magnetic configuration. Using analytical expressions for hydrodynamic, magnetic and Brownian torques, the stochastic angular momentum equation is determined in the dilute limit conditions under applied magnetic field. Results are compared against experimental ones and excellent agreement is observed. We also estimate the uncertainty in the orientation of the disks due to the Brownian torque when an external magnetic field aligns them. Interestingly, this uncertainty is roughly proportional to the ratio of thermal energy of fluid to the magnetic energy stored in the disks. Our approach can be implemented in many practical applications including biotechnology and multi-functional fluidics. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

Free