Patterns in magnetic granular media at the crossover from two to three dimensions

Area of Science:

• Soft Matter Physics
• Computational Physics
• Materials Science

Background:

• Macroscopic patterns in confined, vibrated, and magnetizable bead systems are well-documented.
• Understanding pattern selection in quasi-two-dimensional (2D) systems is crucial for materials design.
• The influence of transitioning from 2D to three-dimensional (3D) confinement on pattern formation remains less explored.

Purpose of the Study:

• To investigate the impact of cell geometry on pattern selection in confined, vibrated, and magnetizable bead systems.
• To explore pattern transitions as systems move from quasi-2D to 3D confinement.
• To analyze the relationship between geometric transitions and changes in system order.

Main Methods:

• Three-dimensional particle-based simulations were employed.
• Simulations focused on confined, vibrated, and magnetizable bead systems.
• System dimensionality was systematically varied from quasi-2D to 3D.

Main Results:

• Previously observed patterns like hexagonal crystals and labyrinthine structures were reproduced in quasi-2D systems.
• In systems transitioning to 3D, labyrinthine branches shortened and were replaced by upright triangular triplets.
• These triplets self-organized into a herringbone pattern, accompanied by increased translational and orientational order.

Conclusions:

• Cell geometry significantly influences pattern selection in these complex bead systems.
• A distinct transition to a herringbone pattern occurs at the crossover from 2D to 3D confinement.
• This geometric transition is directly linked to enhanced collective ordering within the system.