Magnetodynamical response of large-area close-packed arrays of circular dots fabricated by nanosphere lithography
| Autor: | E. K. Semenova(1), F. Montoncello (2), S. Tacchi (3, 6) G. Durr (4), E. Sirotkin (5), E. Ahmad (5), M. Madami (3), G. Gubbiotti (3, S. Neusser (4), D. Grundler (4), F. Y. Ogrin (5), R. J. Hicken (5), V. V. Kruglyak (5), D. V. Berkov (1), N. L. Gorn (1), L. Giovannini (2) |
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| Rok vydání: | 2013 |
| Předmět: |
simulazioni micromagnetiche
Materials science cicli di isteresi cristalli magnonici onde di spin litografia Brillouin light scattering 02 engineering and technology 01 natural sciences Light scattering Magnetization Lattice constant Optics 0103 physical sciences Hexagonal lattice 010306 general physics Anisotropy Condensed matter physics business.industry 021001 nanoscience & nanotechnology Condensed Matter Physics Electronic Optical and Magnetic Materials Brillouin zone Hysteresis Nanosphere lithography 0210 nano-technology business |
| Zdroj: | Physical review. B, Condensed matter and materials physics (Online) 87 (2013): 174432. doi:10.1103/PhysRevB.87.174432 info:cnr-pdr/source/autori:E. K. Semenova(1), F. Montoncello (2), S. Tacchi (3,6) G. Durr (4), E. Sirotkin (5), E. Ahmad (5), M. Madami (3), G. Gubbiotti (3,6), S. Neusser (4), D. Grundler (4), F. Y. Ogrin (5), R. J. Hicken (5), V. V. Kruglyak (5), D. V. Berkov (1), N. L. Gorn (1), and L. Giovannini (2)/titolo:Magneto-dynamical response of large-area close-packed arrays of circular dots fabricated by nano-sphere lithography/doi:10.1103%2FPhysRevB.87.174432/rivista:Physical review. B, Condensed matter and materials physics (Online)/anno:2013/pagina_da:174432/pagina_a:/intervallo_pagine:174432/volume:87 |
| ISSN: | 1550-235X 1098-0121 |
| Popis: | We report a combined experimental and theoretical study of the quasistatic hysteresis and dynamic excitations in large-area arrays of NiFe nanodisks forming a hexagonal lattice with the lattice constant of 390 nm. Arrays were fabricated by patterning a 20-nm-thick NiFe film using the etched nanosphere lithography. We have studied a close-packed (edge-to-edge separation between disks dcp = 65 nm) and an ultraclosed packed (ducp = 20 nm) array. Hysteresis loops for both arrays were qualitatively similar and nearly isotropic, i.e., independent on the in-plane external field orientation. The shape of these loops revealed that magnetization reversal is governed by the formation and expulsion of vortices inside the nanodisks. When we assumed that the nanodisks’ magnetization significantly decreases near their edges, micromagnetic simulations with material parameters deter-mined independently from continuous film measu-rements could satisfactorily reproduce the hysteresis. Despite the isotropic hysteresis, significant in-plane anisotropy of the dynamic response of the ultraclose-packed array was found experimentally by the all-electrical spin-wave spectroscopy and Brillouin light scattering. Dynamical simulations could successfully reproduce the difference between excitation spectra for fields directed along the two main symmetry axes of the hexagonal lattice. Simulations revealed that this difference is caused by the magnetodipolar interaction between nanodisks, which leads to a strong variation of the spatial distribution of the oscillation power both for bulk and edge modes as a function of the bias field orientation. Comparison of simulated and measured frequencies enabled the unambiguous identification of experimentally observed modes. Results of this systematic research are relevant both for fundamental studies of spin-wave modes in patterned magnetic structures and for the design of magnonic crystals for potential applications as, e.g., spin-wave guides and filters. |
| Databáze: | OpenAIRE |
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