Degradation of domains with sequential field application

• Published in: arXiv.org
• Main Author: Caballero, Nirvana
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 20.09.2021
• Subjects: Domain walls; Exponents; Ferromagnetic films; Ferromagnetic materials; Kerr effects; Kerr magnetooptical effect; Mathematical models; Order parameters; Physics - Disordered Systems and Neural Networks; Physics - Mesoscale and Nanoscale Physics; Reduction; Roughness
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2009.14205

Recent experiments show striking unexpected features when alternating square magnetic field pulses are applied to ferromagnetic samples: domains show area reduction and domains walls change their roughness. We explain these phenomena with a simple scalar-field model, using a numerical protocol that mimics the experimental one. For a bubble and a stripe domain, we reproduce the experimental findings: The domains shrink by a combination of linear and exponential behavior. We also reproduce the roughness exponents found in the experiments. Our results suggest that the observed effects are due to a change in the disorder correlation length when the domain walls are subject to alternating fields during the first cycles, where the initial state of the interface plays a crucial role. Finally, our simulations explain the area loss by the interplay between disorder effects and effective fields induced by the local domain curvature.