Spin waves in magnetic thin films: new types of solitons and electrical control
| dc.contributor.author | Wang, Zihui, author | |
| dc.contributor.author | Wu, Mingzhong, advisor | |
| dc.contributor.author | Patton, Carl, committee member | |
| dc.contributor.author | Eykholt, Richard, committee member | |
| dc.contributor.author | Camley, Robert E., committee member | |
| dc.contributor.author | Marconi, Mario C., committee member | |
| dc.date.accessioned | 2017-06-09T15:40:55Z | |
| dc.date.available | 2017-06-09T15:40:55Z | |
| dc.date.issued | 2017 | |
| dc.description.abstract | New types of spin-wave solitons in magnetic thin films and the methods to control spin waves electrically are studied in this thesis. In the first part, the first observation of chaotic spin-wave solitons in yttrium iron garnet (YIG) thin film-based active feedback rings is presented. At some ring gain levels, one observes the self-generation of a single spin-wave soliton pulse in the ring. When the pulse circulates in the ring, its amplitude varies chaotically with time. The excitation of dark spin-wave envelope solitons in YIG thin film strips is also described. The formation of a pair of black solitons with a phase jump of 180° is observed for the first time. The excitation of bright solitons in the case of repulsive nonlinearity is also observed and is reproduced by a numerical simulation based on a high-order nonlinear Schrödinger equation. In the second part, the control of magnetization relaxation in ferromagnetic insulators via interfacial spin scattering is presented. In the experiments nanometer-thick YIG/Pt bi-layered structures are used, with the Pt layer biased by an electric voltage. The bias voltage produces a spin current across the Pt layer thickness due to the spin Hall effect. As this current scatters off the YIG surface, it exerts a torque on the YIG surface spins. This torque can reduce or increase the damping and thereby compress or broaden the ferromagnetic resonance linewidth of the YIG film, depending on the field/current configuration. The control of spin waves in a YIG thin film via interfacial spin scattering is also presented. In the experiments a 4.6-µm-thick YIG film strip with a 20-nm-thick Pt capping layer is used. A DC current pulse is applied to the Pt layer and produced a spin current across the Pt layer. As the spin current scatters off the YIG surface, it can either amplify or attenuate spin-wave pulses that travel in the YIG strip, depending on the current/field configuration. | |
| dc.format.medium | born digital | |
| dc.format.medium | doctoral dissertations | |
| dc.identifier | Wang_colostate_0053A_13938.pdf | |
| dc.identifier.uri | http://hdl.handle.net/10217/181303 | |
| dc.language | English | |
| dc.language.iso | eng | |
| dc.publisher | Colorado State University. Libraries | |
| dc.relation.ispartof | 2000-2019 | |
| dc.rights | Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright. | |
| dc.title | Spin waves in magnetic thin films: new types of solitons and electrical control | |
| dc.type | Text | |
| dcterms.rights.dpla | This Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). | |
| thesis.degree.discipline | Physics | |
| thesis.degree.grantor | Colorado State University | |
| thesis.degree.level | Doctoral | |
| thesis.degree.name | Doctor of Philosophy (Ph.D.) |