Spin-wave dispersion of nanostructured magnonic crystals with periodic defects
The spin-wave dispersions in nanostructured magnonic crystals with periodic defects have been mapped by Brillouin light scattering. The otherwise perfect crystals are one-dimensional arrays of alternating 460nm-wide Ni80Fe20 stripes and 40nm-wide air gaps, where one in ten Ni80Fe20 stripes is a defe...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2016-11-01
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| Series: | AIP Advances |
| Online Access: | http://dx.doi.org/10.1063/1.4967334 |
| _version_ | 1811235727768289280 |
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| author | V. L. Zhang H. S. Lim S. C. Ng M. H. Kuok X. Zhou A. O. Adeyeye |
| author_facet | V. L. Zhang H. S. Lim S. C. Ng M. H. Kuok X. Zhou A. O. Adeyeye |
| author_sort | V. L. Zhang |
| collection | DOAJ |
| description | The spin-wave dispersions in nanostructured magnonic crystals with periodic defects have been mapped by Brillouin light scattering. The otherwise perfect crystals are one-dimensional arrays of alternating 460nm-wide Ni80Fe20 stripes and 40nm-wide air gaps, where one in ten Ni80Fe20 stripes is a defect of width other than 460 nm. Experimentally, the defects are manifested as additional Brillouin peaks, lying within the first and second bandgaps of the perfect crystal, whose frequencies decrease with increasing defect stripe width. Finite-element calculations, based on a supercell comprising one defect and nine perfect Py stripes, show that the defect modes are localized about the defects, with the localization exhibiting an approximate U-shaped dependence on defect size. Calculations also reveal extra magnon branches and the opening of mini-bandgaps, within the allowed bands of the perfect crystal, arising from Bragg reflections at the boundaries of the shorter supercell Brillouin zone. Simulated magnetization profiles of the band-edge modes of the major and mini-bandgaps reveal their different symmetries and localization properties. The findings could find application in microwave magnonic devices like single-frequency passband spin-wave filters. |
| first_indexed | 2024-04-12T11:57:20Z |
| format | Article |
| id | doaj.art-d2eec2a5e7dd4d7fa4c38870d2b5d91c |
| institution | Directory Open Access Journal |
| issn | 2158-3226 |
| language | English |
| last_indexed | 2024-04-12T11:57:20Z |
| publishDate | 2016-11-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | AIP Advances |
| spelling | doaj.art-d2eec2a5e7dd4d7fa4c38870d2b5d91c2022-12-22T03:33:58ZengAIP Publishing LLCAIP Advances2158-32262016-11-01611115106115106-710.1063/1.4967334020611ADVSpin-wave dispersion of nanostructured magnonic crystals with periodic defectsV. L. Zhang0H. S. Lim1S. C. Ng2M. H. Kuok3X. Zhou4A. O. Adeyeye5Department of Physics, National University of Singapore, Singapore 117551Department of Physics, National University of Singapore, Singapore 117551Department of Physics, National University of Singapore, Singapore 117551Department of Physics, National University of Singapore, Singapore 117551Dept. of Electrical & Computer Engineering, National University of Singapore, Singapore 117576Dept. of Electrical & Computer Engineering, National University of Singapore, Singapore 117576The spin-wave dispersions in nanostructured magnonic crystals with periodic defects have been mapped by Brillouin light scattering. The otherwise perfect crystals are one-dimensional arrays of alternating 460nm-wide Ni80Fe20 stripes and 40nm-wide air gaps, where one in ten Ni80Fe20 stripes is a defect of width other than 460 nm. Experimentally, the defects are manifested as additional Brillouin peaks, lying within the first and second bandgaps of the perfect crystal, whose frequencies decrease with increasing defect stripe width. Finite-element calculations, based on a supercell comprising one defect and nine perfect Py stripes, show that the defect modes are localized about the defects, with the localization exhibiting an approximate U-shaped dependence on defect size. Calculations also reveal extra magnon branches and the opening of mini-bandgaps, within the allowed bands of the perfect crystal, arising from Bragg reflections at the boundaries of the shorter supercell Brillouin zone. Simulated magnetization profiles of the band-edge modes of the major and mini-bandgaps reveal their different symmetries and localization properties. The findings could find application in microwave magnonic devices like single-frequency passband spin-wave filters.http://dx.doi.org/10.1063/1.4967334 |
| spellingShingle | V. L. Zhang H. S. Lim S. C. Ng M. H. Kuok X. Zhou A. O. Adeyeye Spin-wave dispersion of nanostructured magnonic crystals with periodic defects AIP Advances |
| title | Spin-wave dispersion of nanostructured magnonic crystals with periodic defects |
| title_full | Spin-wave dispersion of nanostructured magnonic crystals with periodic defects |
| title_fullStr | Spin-wave dispersion of nanostructured magnonic crystals with periodic defects |
| title_full_unstemmed | Spin-wave dispersion of nanostructured magnonic crystals with periodic defects |
| title_short | Spin-wave dispersion of nanostructured magnonic crystals with periodic defects |
| title_sort | spin wave dispersion of nanostructured magnonic crystals with periodic defects |
| url | http://dx.doi.org/10.1063/1.4967334 |
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