Droplet nucleation and domain wall motion in a bounded interval

Area of Science:

• Physics
• Materials Science
• Statistical Mechanics

Background:

• Noise-induced transitions are crucial in understanding magnetic phenomena.
• The Ginzburg-Landau model describes phase transitions and magnetization dynamics.
• Understanding activation barriers is key for predicting system stability.

Purpose of the Study:

• To investigate noise-induced magnetization reversal in a spatially extended Ginzburg-Landau model.
• To analyze the impact of interval length on activation barriers and Kramers rate prefactors.
• To identify transitions between different activation regimes.

Main Methods:

• Adaptation of the Coleman-Langer approach for false vacuum decay.
• Analysis of a classical Ginzburg-Landau model under weak spatiotemporal noise.
• Mathematical determination of activation barrier and prefactor dependence on interval length.

Main Results:

• A transition between activation regimes was observed as the interval length increased.
• The Kramers rate prefactor was found to diverge at this transition point.
• The study quantifies the relationship between system size and reversal dynamics.

Conclusions:

• The observed transitions in activation regimes are a general feature of bistable, spatially extended classical models.
• This research provides insights into the fundamental mechanisms of noise-driven transitions.
• Findings have implications for magnetic storage and other systems exhibiting similar dynamics.