Edge transport at the boundary between topologically equivalent lattices

Edge currents of paramagnetic colloidal particles propagate at the edge between two topologically equivalent magnetic lattices of different lattice constant when the system is driven with periodic modulation loops of an external magnetic field.

Download Full-text

Simultaneous polydirectional transport of colloidal bipeds

Nature Communications ◽

10.1038/s41467-020-18467-9 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Mahla Mirzaee-Kakhki ◽

Adrian Ernst ◽

Daniel de las Heras ◽

Maciej Urbaniak ◽

Feliks Stobiecki ◽

...

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

External Field ◽

Colloidal Particles ◽

Addition Reaction ◽

Lab On A Chip ◽

Magnetic Pattern ◽

Colloidal Spheres ◽

Colloidal Science ◽

Colloidal Rods

Abstract Detailed control over the motion of colloidal particles is relevant in many applications in colloidal science such as lab-on-a-chip devices. Here, we use an external magnetic field to assemble paramagnetic colloidal spheres into colloidal rods of several lengths. The rods reside above a square magnetic pattern and are transported via modulation of the direction of the external magnetic field. The rods behave like bipeds walking above the pattern. Depending on their length, the bipeds perform topologically distinct classes of protected walks. We design parallel polydirectional modulation loops of the external field that command up to six classes of bipeds to walk on distinct predesigned paths. Using such loops, we induce the collision of reactant bipeds, their polymerization addition reaction to larger bipeds, the separation of product bipeds from the educts, the sorting of different product bipeds, and also the parallel writing of a word consisting of several letters. Our ideas and methodology might be transferred to other systems for which topological protection is at work.

Download Full-text

Characteristics of Ultrasound Propagation in a Magnetic Fluid Under Uniform Magnetic Field

Volume 2: Symposia, Parts A, B, and C ◽

10.1115/fedsm2003-45041 ◽

2003 ◽

Author(s):

Masaaki Motozawa ◽

Tatsuo Sawada

Keyword(s):

Magnetic Field ◽

External Magnetic Field ◽

Magnetic Fluid ◽

Uniform Magnetic Field ◽

Colloidal Particles ◽

Magnetic Field Intensity ◽

Magnetic Field Direction ◽

Ultrasound Propagation ◽

Ultrasonic Propagation ◽

The Magnetic Field

When an external magnetic field is applied to a magnetic fluid, some of the colloidal particles coagulate and form chain-like clusters. Properties of ultrasonic propagation wave are changed by these chain-like clusters. We carried out measurement of the ultrasonic propagation velocity in a magnetic fluid. Measurement were made by changing the magnetic field intensity from 0 mT to 570 mT, and the angle between the magnetic field direction and direction of the ultrasound propagation from 0° to 180°. The ultrasound frequencies were 1 MHz, 2 MHz and 4 MHz. Some of experimental results for the characteristics of ultrasound propagation in a magnetic fluid under a uniform magnetic field were reported.

Download Full-text

MAGNETORHEOLOGICAL CHARACTERIZATION OF HOLLOW POLYMER/MAGNETITE MICROSPHERICAL COMPOSITE

International Journal of Modern Physics B ◽

10.1142/s0217979209063067 ◽

2009 ◽

Vol 23 (17) ◽

pp. 3613-3618 ◽

Cited By ~ 3

Author(s):

FEI FEI FANG ◽

JI HYE KIM ◽

HYOUNG JIN CHOI

Keyword(s):

Magnetic Field ◽

Magnetic Property ◽

External Magnetic Field ◽

Shear Viscosity ◽

Colloidal Particles ◽

Rheological Characteristics ◽

Carrier Liquid ◽

Magnetic Field Generator ◽

Mr Characteristics

Magnetorheological (MR) suspensions, composed of colloidal particles dispersed in a carrier liquid, possess tunable rheological characteristics by applying an external magnetic field, showing dramatic changes of yield stress and shear viscosity caused by transformation between solid-like to liquid-like state. As a new MR material, we synthesized hollow polystyrene/magnetite (PS/Fe3O4) microspherical composite. Morphology of the PS obtained and the loaded magnetite were examined via SEM, and TGA spectra confirmed the composition. Magnetic property was tested by VSM data. MR characteristics of MR suspension based on PS / Fe 3 O 4 composites were studied via both steady shear and oscillatory tests using a rotational rheometer equipped with a magnetic field generator.

Download Full-text