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Surface effects on ferromagnetic resonance in magnetic nanocubes
R Bastardis1, F Vernay1, D-A Garanin2
1Laboratoire PROMES CNRS (UPR-8521), Université de Perpignan Via Domitia, Rambla de la thermodynamique, Tecnosud, F-66100 Perpignan, France.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|November 15, 2016
Summary
Surface anisotropy significantly impacts spin-wave excitations in magnetic nanoclusters. This study develops a numerical method to analyze these effects, revealing distinct spectral features in iron nanocubes.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Understanding spin-wave excitations in magnetic nanoclusters is crucial for developing advanced magnetic devices.
- Surface anisotropy plays a significant role in the magnetic properties of nanomaterials.
- Recent advancements in nano-element synthesis necessitate accurate theoretical models.
Purpose of the Study:
- To investigate the influence of surface anisotropy on spin-wave excitation spectra.
- To develop and validate a general numerical method for analyzing magnetic nanoclusters.
- To compute the absorbed power spectrum and identify spin-wave resonances in iron nanocubes.
Main Methods:
- Development of a general numerical method based on the Landau-Lifshitz equation.
- Linearization of the Landau-Lifshitz equation for eigenvalue problems.
- Application of symplectic techniques for solving the equation.
- Comparison with finite-size linear spin-wave theory for box-shaped clusters.
Main Results:
- The numerical method successfully disentangles core and surface spin contributions to spectral weight and absorbed power.
- For an iron nanocube, a low-energy peak around 10 GHz (uniform mode) and high-frequency exchange-mode peaks around 60 GHz were predicted.
- Surface anisotropy and free boundaries were shown to influence the spin-wave spectrum, with surface spins contributing to low-energy features.
Conclusions:
- The developed numerical method provides accurate predictions for spin-wave spectra in magnetic nanoclusters.
- Surface anisotropy is a key factor determining the spin-wave spectrum and absorbed power.
- The study offers insights into the magnetic resonance behavior of iron nanocubes, relevant for spintronic applications.
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