Signatures of ballistic and diffusive transport in the time-dependent Kerr-response of magnetic materials
We calculate the influence of diffusive and ballistic transport on ultrafast magnetization in thick metallic films. When only diffusive transport is present, gradients of magnetization in the material remain up to picosecond timescales. In contrast, when ballistic transport dominates, the magnetizat...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2025-01-01
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| Series: | New Journal of Physics |
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| Online Access: | https://doi.org/10.1088/1367-2630/adce23 |
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| author | Sanjay Ashok Jonas Hoefer Martin Stiehl Martin Aeschlimann Hans Christian Schneider Baerbel Rethfeld Benjamin Stadtmüller |
| author_facet | Sanjay Ashok Jonas Hoefer Martin Stiehl Martin Aeschlimann Hans Christian Schneider Baerbel Rethfeld Benjamin Stadtmüller |
| author_sort | Sanjay Ashok |
| collection | DOAJ |
| description | We calculate the influence of diffusive and ballistic transport on ultrafast magnetization in thick metallic films. When only diffusive transport is present, gradients of magnetization in the material remain up to picosecond timescales. In contrast, when ballistic transport dominates, the magnetization changes homogeneously in space. We calculate the measurable magneto-optical responses for a 40 nm nickel film. Although the resulting Kerr rotation dynamics are very similar in the two limits of transport, our simulations reveal a clear signature of magnetization gradients in the Kerr ellipticity dynamics, namely a strong probe-angle dependence for the case when diffusive transport allows gradients to persist. We then compare our theoretical results with probe-angle dependent complex magneto-optical Kerr effect measurements on an optically excited 40 nm nickel film. The angle dependence of the measured Kerr signals closely matches the simulated response with diffusive transport. We conclude that the influence of ballistic transport on ultrafast magnetization dynamics in such films is negligible. |
| format | Article |
| id | doaj-art-6ba6f1fbb0b8439a86e39afa672cc415 |
| institution | DOAJ |
| issn | 1367-2630 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj-art-6ba6f1fbb0b8439a86e39afa672cc4152025-08-20T03:05:45ZengIOP PublishingNew Journal of Physics1367-26302025-01-0127606300110.1088/1367-2630/adce23Signatures of ballistic and diffusive transport in the time-dependent Kerr-response of magnetic materialsSanjay Ashok0Jonas Hoefer1Martin Stiehl2Martin Aeschlimann3https://orcid.org/0000-0003-3413-5029Hans Christian Schneider4Baerbel Rethfeld5https://orcid.org/0009-0008-9921-4127Benjamin Stadtmüller6https://orcid.org/0000-0001-8439-434XDepartment of Physics and OPTIMAS Research Center, RPTU Kaiserslautern-Landau , Erwin Schrödinger Straße 46, 67663 Kaiserslautern, GermanyDepartment of Physics and OPTIMAS Research Center, RPTU Kaiserslautern-Landau , Erwin Schrödinger Straße 46, 67663 Kaiserslautern, GermanyDepartment of Physics and OPTIMAS Research Center, RPTU Kaiserslautern-Landau , Erwin Schrödinger Straße 46, 67663 Kaiserslautern, GermanyDepartment of Physics and OPTIMAS Research Center, RPTU Kaiserslautern-Landau , Erwin Schrödinger Straße 46, 67663 Kaiserslautern, GermanyDepartment of Physics and OPTIMAS Research Center, RPTU Kaiserslautern-Landau , Erwin Schrödinger Straße 46, 67663 Kaiserslautern, GermanyDepartment of Physics and OPTIMAS Research Center, RPTU Kaiserslautern-Landau , Erwin Schrödinger Straße 46, 67663 Kaiserslautern, GermanyDepartment of Physics and OPTIMAS Research Center, RPTU Kaiserslautern-Landau , Erwin Schrödinger Straße 46, 67663 Kaiserslautern, Germany; Experimentalphysik II, Institute of Physics, Augsburg University , 86159 Augsburg, GermanyWe calculate the influence of diffusive and ballistic transport on ultrafast magnetization in thick metallic films. When only diffusive transport is present, gradients of magnetization in the material remain up to picosecond timescales. In contrast, when ballistic transport dominates, the magnetization changes homogeneously in space. We calculate the measurable magneto-optical responses for a 40 nm nickel film. Although the resulting Kerr rotation dynamics are very similar in the two limits of transport, our simulations reveal a clear signature of magnetization gradients in the Kerr ellipticity dynamics, namely a strong probe-angle dependence for the case when diffusive transport allows gradients to persist. We then compare our theoretical results with probe-angle dependent complex magneto-optical Kerr effect measurements on an optically excited 40 nm nickel film. The angle dependence of the measured Kerr signals closely matches the simulated response with diffusive transport. We conclude that the influence of ballistic transport on ultrafast magnetization dynamics in such films is negligible.https://doi.org/10.1088/1367-2630/adce23ultrafast magnetization dynamicsdiffusive transportballistic transportmagneto-optic Kerr effectnanoscalemagnetism |
| spellingShingle | Sanjay Ashok Jonas Hoefer Martin Stiehl Martin Aeschlimann Hans Christian Schneider Baerbel Rethfeld Benjamin Stadtmüller Signatures of ballistic and diffusive transport in the time-dependent Kerr-response of magnetic materials New Journal of Physics ultrafast magnetization dynamics diffusive transport ballistic transport magneto-optic Kerr effect nanoscale magnetism |
| title | Signatures of ballistic and diffusive transport in the time-dependent Kerr-response of magnetic materials |
| title_full | Signatures of ballistic and diffusive transport in the time-dependent Kerr-response of magnetic materials |
| title_fullStr | Signatures of ballistic and diffusive transport in the time-dependent Kerr-response of magnetic materials |
| title_full_unstemmed | Signatures of ballistic and diffusive transport in the time-dependent Kerr-response of magnetic materials |
| title_short | Signatures of ballistic and diffusive transport in the time-dependent Kerr-response of magnetic materials |
| title_sort | signatures of ballistic and diffusive transport in the time dependent kerr response of magnetic materials |
| topic | ultrafast magnetization dynamics diffusive transport ballistic transport magneto-optic Kerr effect nanoscale magnetism |
| url | https://doi.org/10.1088/1367-2630/adce23 |
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