Title: | Optimal Control of Magnetization Reversal in a Monodomain Particle by Means of Applied Magnetic Field |
Author: |
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Date: | 2021-04-29 |
Language: | English |
Scope: | 177206 |
University/Institute: | Háskóli Íslands University of Iceland |
School: | Verkfræði- og náttúruvísindasvið (HÍ) School of Engineering and Natural Sciences (UI) |
Department: | Raunvísindastofnun (HÍ) Science Institute (UI) |
Series: | Physical Review Letters;126(17) |
ISSN: | 0031-9007 1079-7114 (eISSN) |
DOI: | 10.1103/PhysRevLett.126.177206 |
Subject: | General Physics and Astronomy; Eðlisfræði; Stærðfræðileg eðlisfræði; Magnetization switching; spin dynamics; magnetic nanoparticles; Landau-Lifshitz-Gilbert equation; Mathematical physics methods |
URI: | https://hdl.handle.net/20.500.11815/2902 |
Citation:Kwiatkowski, G. J., Badarneh, M. H. A., Berkov, D.V., & Bessarab, P. F. (2021). Optimal Control of Magnetization Reversal in a Monodomain Particle by Means of Applied Magnetic Field. Physical Review Letters 126, 177206. doi: 10.1103/PhysRevLett.126.177206
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Abstract:A complete analytical solution to the optimal reversal of a macrospin with easy-axis anisotropy is presented. An optimal control path minimizing the energy cost of the reversal is identified and used to derive the time-dependent direction and amplitude of the optimal switching field. The minimum energy cost of the reversal scales inversely with the switching time for fast switching, follows exponential asymptotics for slow switching, and reaches the lower limit proportional to the energy barrier between the target states and to the damping parameter at infinitely long switching time. For a given switching time, the energy cost is never smaller than that for a free macrospin. This limitation can be bypassed by adding a hard anisotropy axis that activates the internal torque in the desired switching direction, thereby significantly reducing the energy cost. A comparison between the calculated optimal control path and minimum energy path reveals that optimal control does not translate to the minimization of the energy barrier but signifies effective use of the system’s internal dynamics to aid the desired magnetic transition.
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Description:Post-print (lokagerð höfundar)
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