Strong Magnetic Field Induced Segregation and Self-Assembly of Micrometer Sized Non-Magnetic Particles

Abstract

Abstract-Micrometer and sub-micrometer sized non-magnetic particles were manipulated by an external strong magnetic field (e.g., 10 Tesla) with a high gradient. During the strong magnetic field effects, segregation of the non-magnetic particles was observed which could not be realised only with gravitational field. Numerical calculations were subsequently carried out to understand the effects on the insulating particles in a conductive liquid matrix. The migration of micrometer sized particles is obviously enhanced by the magnetic field gradient. Combining the experimental results and theoretical analysis, particle-particle magnetic interaction was found to influence the overall segregation of the particles as well. Magnetised by the strong magnetic field, magnetic interaction between non-magnetic particles becomes dominant and a self-assembly behavior can be demonstrated. Various factors such as the magnetic dipole-dipole interaction and chainchain interaction, are governing the particles assembly. According to calculations, magnetic field should be strong enough, at least 7 T in order to obtain the assembly morphologies in the present case.

Strong Magnetic Field Effect on Surface Tension Associated with an Interfacial Magnetic Pressure

“…A water cooling system is installed to keep the inner wall of the magnet at a temperature below 40 °C. The experimental apparatus has been schematically presented elsewhere . The magnetic field distribution together with the field gradient along the vertical direction was measured with a magnetic fluxmeter (HT700SP, Shanghai YAHAO).…”

“…The experimental apparatus has been schematically presented elsewhere. 17 The magnetic field distribution together with the field gradient along the vertical direction was measured with a magnetic fluxmeter (HT700SP, Shanghai YAHAO). The furnace consisting of nonmagnetic materials has a negligible influence on the magnetic field distribution.…”

Strong magnetic field-induced segregation and alignment of nonmagnetic particles

“…10 The sample was initially heated to 700 C and kept for a preset time under the magnetic field. A more detailed description of the apparatus is provided elsewhere.…”