Confined magnon transport in low dimensional ferromagnetic structures

Ahmed, M 2017, Confined magnon transport in low dimensional ferromagnetic structures, Doctor of Philosophy (PhD), Science, RMIT University.


Document type: Thesis
Collection: Theses

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Title Confined magnon transport in low dimensional ferromagnetic structures
Author(s) Ahmed, M
Year 2017
Abstract Magnons are the quantum particles of spin waves. They are investigated as a potential candidate for quantum and classical communication and computation. Dispersion in the spin lattice restricts the effective range of magnons, thus reducing their efficacy as a long range information carrier. When confronted with a similar issue in optics, it was solved by confining the optical pulse in a transverse potential of a variable refractive index, i.e. an optical fibre. Extending the analogy to magnonics, we explore avenues for the use of external electric and magnetic fields to counteract dispersion. We simulate the propagation of the magnon in one- and two-dimensional media under spatio-temporally varying electric and magnetic fields, thus creating either a one- or two-dimensional spin guide, as required. We show that the transverse confinement vastly mitigates the magnon dispersion in one and two-dimensional ferromagnets, extending the effective magnon range. We perform all calculations in the framework of the Heisenberg model. In a two-dimensional medium, we show that two proximal spin-guides can be coupled and can exchange population. We then show a complete model of a magnonic Michelson interferometer using two-dimensional spin-guides, which can be used to perform classical and quantum logical operations. In the final chapter, we describe protocols to convert a single spin excitation into a magnon, and convert a static magnon into a moving magnon in a spin chain to realise an magnonic flying qubit. We show that a magnonic mediated interaction can be performed in two distant qubits that are not directly coupled.
Degree Doctor of Philosophy (PhD)
Institution RMIT University
School, Department or Centre Science
Subjects Quantum Physics not elsewhere classified
Quantum Information, Computation and Communication
Keyword(s) Magnon
Spin waves
Quantum transport
Quantum computation
Interferometer
Spin guide
Michelson interferomater
Confined magnon transport
Spin chain
Spin sheet
Ferromagnet
Heisenberg model
Kane architecture
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Created: Fri, 17 Nov 2017, 09:33:35 EST by Adam Rivett
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