Klik, Ivo, McHugh, James, Chantrell, Roy W. orcid.org/0000-0001-5410-5615 et al. (1 more author) (2018) Debye formulas for a relaxing system with memory. Scientific Reports. 3271. ISSN 2045-2322
Abstract
Rate (master) equations are ubiquitous in statistical physics, yet, to the best of our knowledge, a rate equation with memory has previously never been considered. We write down an integro-differential rate equation for the evolution of a thermally relaxing system with memory. For concreteness we adopt as a model a single-domain magnetic particle driven by a small ac field and derive the modified Debye formulas. For any memory time Θ the in-phase component of the resultant ac susceptibility is positive at small probing frequencies ω, but becomes negative at large ω. The system thus exhibits frequency induced diamagnetism. For comparison we also consider particle pairs with dipolar coupling. The memory effect is found to be enhanced by ferromagnetic coupling and suppressed by antiferromagnetic coupling. Numerical calculations support the prediction of a negative susceptibility which arises from a phase shift induced by the memory effect. It is proposed that the onset of frequency induced diamagnetism represents a viable experimental signature of correlated noise.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © The Author(s) 2018 |
Dates: |
|
Institution: | The University of York |
Academic Units: | The University of York The University of York > Faculty of Sciences (York) > Physics (York) |
Depositing User: | Pure (York) |
Date Deposited: | 14 Mar 2018 17:30 |
Last Modified: | 22 Dec 2024 00:12 |
Published Version: | https://doi.org/10.1038/s41598-018-21028-2 |
Status: | Published online |
Refereed: | Yes |
Identification Number: | 10.1038/s41598-018-21028-2 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:128564 |