Magnetic ghosts and monopoles

TL;DR

This paper investigates how magnetic beads arranged in chains and rings can form stable defects called 'ghost junctions' that mimic magnetic monopoles, revealing new insights into the interplay between local frustration and global magnetic properties.

Contribution

It introduces the concept of mechanically stable 'ghost junctions' in magnetic bead arrangements that behave like magnetic monopoles, bridging microscopic frustration and macroscopic magnetic phenomena.

Findings

Stable 'ghost junctions' can be created in magnetic bead systems.

These defects act as macroscopic magnetic monopoles.

The behavior resembles phenomena observed in spin ice systems.

Abstract

While the physics of equilibrium systems composed of many particles is well known, the interplay between small-scale physics and global properties is still a mystery for athermal systems. Non-trivial patterns and metastable states are often reached in those systems. We explored the various arrangements adopted by magnetic beads along chains and rings. Here, we show that it is possible to create mechanically stable defects in dipole arrangements keeping the memory of dipole frustration. Such defects, nicknamed "ghost junctions", seem to act as macroscopic magnetic monopoles, in a way reminiscent of spin ice systems.