Domain wall dynamics in ferromagnetic nanostructures
Topological defects of domain walls (DWs) in ferromagnetic materials are of paramount importance as regard to both fundamental physics as well as potential applications in non-volatile memory and spin logic devices. This thesis investigates topological manipulation and dynamics in both in-plane and...
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| Format: | Thesis |
| Language: | English |
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2017
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| Online Access: | http://hdl.handle.net/10356/72355 |
| _version_ | 1826123249605410816 |
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| author | Maddu Ramu |
| author2 | Lew Wen Siang |
| author_facet | Lew Wen Siang Maddu Ramu |
| author_sort | Maddu Ramu |
| collection | NTU |
| description | Topological defects of domain walls (DWs) in ferromagnetic materials are of paramount importance as regard to both fundamental physics as well as potential applications in non-volatile memory and spin logic devices. This thesis investigates topological manipulation and dynamics in both in-plane and out-of-plane magnetized nanostructures. For in-plane nanostructures, a technique to control, detect and rectify the topological nature of a transverse DW was proposed and experimentally verified. The topological defects play a crucial role in DWs interaction, leading to mutual annihilation or formation of bound states. This causes stochasticity in the DW generation. A method whereby single DW can be generated deterministically was demonstrated and experimentally verified. Lastly, dynamics of chiral Néel DWs driven by spin orbit torques (SOTs) in perpendicularly magnetized heterostructures were studied. A cross over from the field dominated DW depinning to current dominated DW depinning was established as the magnitude of the current was increased. The SOT in concert with Dzyaloshinskii-Moriya interaction (DMI) was correlated to this anomaly. |
| first_indexed | 2024-10-01T06:01:34Z |
| format | Thesis |
| id | ntu-10356/72355 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T06:01:34Z |
| publishDate | 2017 |
| record_format | dspace |
| spelling | ntu-10356/723552023-02-28T23:47:58Z Domain wall dynamics in ferromagnetic nanostructures Maddu Ramu Lew Wen Siang School of Physical and Mathematical Sciences DRNTU::Science::Physics Topological defects of domain walls (DWs) in ferromagnetic materials are of paramount importance as regard to both fundamental physics as well as potential applications in non-volatile memory and spin logic devices. This thesis investigates topological manipulation and dynamics in both in-plane and out-of-plane magnetized nanostructures. For in-plane nanostructures, a technique to control, detect and rectify the topological nature of a transverse DW was proposed and experimentally verified. The topological defects play a crucial role in DWs interaction, leading to mutual annihilation or formation of bound states. This causes stochasticity in the DW generation. A method whereby single DW can be generated deterministically was demonstrated and experimentally verified. Lastly, dynamics of chiral Néel DWs driven by spin orbit torques (SOTs) in perpendicularly magnetized heterostructures were studied. A cross over from the field dominated DW depinning to current dominated DW depinning was established as the magnitude of the current was increased. The SOT in concert with Dzyaloshinskii-Moriya interaction (DMI) was correlated to this anomaly. Doctor of Philosophy (SPMS) 2017-06-13T03:53:18Z 2017-06-13T03:53:18Z 2017 Thesis Maddu Ramu. (2017). Domain wall dynamics in ferromagnetic nanostructures. Doctoral thesis, Nanyang Technological University, Singapore. http://hdl.handle.net/10356/72355 10.32657/10356/72355 en 185 p. application/pdf |
| spellingShingle | DRNTU::Science::Physics Maddu Ramu Domain wall dynamics in ferromagnetic nanostructures |
| title | Domain wall dynamics in ferromagnetic nanostructures |
| title_full | Domain wall dynamics in ferromagnetic nanostructures |
| title_fullStr | Domain wall dynamics in ferromagnetic nanostructures |
| title_full_unstemmed | Domain wall dynamics in ferromagnetic nanostructures |
| title_short | Domain wall dynamics in ferromagnetic nanostructures |
| title_sort | domain wall dynamics in ferromagnetic nanostructures |
| topic | DRNTU::Science::Physics |
| url | http://hdl.handle.net/10356/72355 |
| work_keys_str_mv | AT madduramu domainwalldynamicsinferromagneticnanostructures |