scholarly journals Transverse complex magnetic susceptibility of single-domain ferromagnetic particles with uniaxial anisotropy subjected to a longitudinal uniform magnetic field

1997 ◽  
Vol 56 (6) ◽  
pp. 3325-3337 ◽  
Author(s):  
Yu P. Kalmykov ◽  
W. T. Coffey
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Uniform Magnetic Field ◽  
Uniaxial Anisotropy ◽  
Single Domain ◽  
Ferromagnetic Particles

Non-Equilibrium Magnetization of a Dilute Suspension of Magnetic Particles

2009 ◽  
Vol 152-153 ◽  
pp. 167-170 ◽  
Author(s):  
Alexander Tyatyushkin
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Heat Generation ◽  
Applied Magnetic Field ◽  
Single Particle ◽  
Uniform Magnetic Field ◽  
Magnetic Particles ◽  
Equilibrium Magnetization ◽  
Dilute Suspension ◽  
Generation Power

A suspension of magnetic particles in a viscous liquid magnetized in an alternating uniform magnetic field is theoretically studied. The suspension is regarded as so dilute that interaction of a single particle with the applied magnetic field can be considered without taking into account the influence of other particles. The complex magnetic susceptibility of the suspension is found as a function of the frequency of the applied magnetic field. The heat generation power density averaged over the period of the oscillations is calculated.

scholarly journals On-demand Ferrofluid Droplet Formation With Non-linear Magnetic Permeability in the Presence of a Non-uniform Magnetic Field

2021 ◽  
Author(s):  
Mohamad Ali Bijarchi ◽  
Mohammad Yaghoobi ◽  
Amirhossein Favakeh ◽  
Mohammad Behshad Shafii
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Uniform Magnetic Field ◽  
Maxwell Equations ◽  
Droplet Diameter ◽  
Droplet Formation ◽  
Bond Number ◽  
On Demand ◽  
Drop On Demand ◽  
The Magnetic Field

Abstract The magnetic actuation of ferrofluid droplets offers an inspiring tool in widespread engineering and biological applications. In this study, the dynamics of ferrofluid droplet generation with a Drop-on-Demand feature under a non-uniform magnetic field is investigated by multiscale numerical modeling. Langevin equation is assumed for ferrofluid magnetic susceptibility due to the strong applied magnetic field. Large and small computational domains are considered. In the larger domain, the magnetic field is obtained by solving Maxwell equations. In the smaller domain, a coupling of continuity, Navier Stokes, two-phase flow, and Maxwell equations are solved by utilizing the magnetic field achieved by the larger domain for the boundary condition. The Finite volume method and coupling of level-set and Volume of Fluid methods are used for solving equations. The droplet formation is simulated in a two-dimensional axisymmetric domain. The method of solving fluid and magnetic equations is validated using a benchmark. Then, ferrofluid droplet formation is investigated experimentally and the numerical results are in good agreement with the experimental data. The effect of 12 dimensionless parameters including the ratio of magnetic, gravitational, and surface tension forces, the ratio of the nozzle and magnetic coil dimensions, and ferrofluid to continuous-phase properties ratios are studied. The results showed that by increasing the magnetic Bond number, gravitational Bond number, Ohnesorge number, dimensionless saturation magnetization, initial magnetic susceptibility of ferrofluid, the generated droplet diameter reduces, whereas the formation frequency increases. The same results were observed when decreasing the ferrite core diameter to outer nozzle diameter, density, and viscosity ratios.

Some magnetic properties of metals. V. Magnetic behaviour of a cylindrical system of electrons for all magnetic fields

1953 ◽  
Vol 216 (1124) ◽  
pp. 118-142 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Wave Function ◽  
Magnetic Susceptibility ◽  
Uniform Magnetic Field ◽  
Magnetic Behaviour ◽  
The Other ◽  
Cylindrical System ◽  
Different Types ◽  
Large Systems

The Wentzel-Kramers-Brillouin method is used to solve the Schrödinger equation for an electron moving in a uniform magnetic field H , the boundary of the system being a cylinder with its axis lying along the direction of the field. It is found that there are two entirely different types of wave-function possible, one type leading to the small Landau diamagnetism of large systems discussed in part I of this series, the other to the larger diamagnetism of small systems discussed in part IV. Taking into account the occupied states of both types, the steady (non-periodic) contributions to the magnetic susceptibility are derived for all fields in both the low- and high-temperature limits, and for most fields at intermediate temperatures.

scholarly journals A Rapid Magnetofluidic Micromixer Using Diluted Ferrofluid

2016 ◽  
Author(s):  
Majid Hejazian ◽  
Nam-Trung Nguyen
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
External Magnetic Field ◽  
Uniform Magnetic Field ◽  
Body Force ◽  
Low Cost ◽  
Magnetic Field Gradient ◽  
Mixing Efficiency ◽  
Biological Assays ◽  
The Magnetic Field

Effective and rapid mixing is essential for various chemical and biological assays. The present work reports a simple and low-cost micromixer based on magnetofluidic actuation. The device takes advantage of magnetoconvective secondary flow, a bulk flow induced by an external magnetic field, for mixing. A paramagnetic stream of diluted ferrofluid and a non-magnetic stream are introduced to a straight microchannel. A permanent magnet placed next to the microchannel induced a non-uniform magnetic field. The magnetic field gradient and the mismatch in magnetic susceptibility between the two streams create a body force, which leads to rapid and efficient mixing. The micromixer reported here could achieve a high throughput and a high mixing efficiency of 90 % in a relatively short microchannel.

scholarly journals Constant-magnetic-field effect in Néel relaxation of single-domain ferromagnetic particles

1995 ◽  
Vol 51 (22) ◽  
pp. 15947-15956 ◽  
Author(s):  
W. T. Coffey ◽  
D. S. F. Crothers ◽  
Yu. P. Kalmykov ◽  
J. T. Waldron
Keyword(s):  
Magnetic Field ◽  
Constant Magnetic Field ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Single Domain ◽  
Néel Relaxation ◽  
Ferromagnetic Particles
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