Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 46 for “"Spin wave"”.
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Suppression of spin wave instabilities in ferrimagnets.
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering, 1966
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Spin wave characterization in a 1D YIG magnonic crystal
… thesis, I will analyze and discuss features of spin wave propagation characteristics measured in a one-dimensional (1D) yttrium iron garnet (YIG) magnonic crystal using time-resolved Brillouin light scattering (TR-BLS) measurements. Magnonic crystals are a promising candidate to aid in …
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Magnetic ordering and spin wave dynamics in transition metal arsenides
Ever since spin orbit torque based switching was proposed in antiferromagnets, there is a growing interest in using a metallic antiferromagnet as an active component of a spintronic device. Arsenic forms a large pool of magnetic metals in combination with transition metal atoms. In this report, we …
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Ab initio calculations of spin wave excitation spectra from time-dependent density functional theory
… of elementary magnetic excitations, so-called spin waves. The theoretical foundation of spin-wave excitations is systematically worked out, the central points of a computer implementation is presented, and results are finally shown. A central property of these calculations is that no …
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Raman scattering in heavy rare earth metals
… ferromagnetic phase. The ferromagnetic acoustic spin wave gap in Dy was observed. To our knowledge this is the first observation of a metallic spin wave by Raman scattering. The light scattering measurement of the spin wave gap energy agrees with and corroborates earlier infrared resonance …
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Study of microwave-assisted magnetization dynamics in magnetic films and structures
Microwave-assisted magnetization reversal (MAMR) has been suggested as an alternative recording scheme to extend areal densities in hard disk drives beyond 1 Tb/in<sup>2</sup>. In this thesis, microwave-assisted magnetization dynamics have been characterized in different spatial regimes by …
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Brillouin scattering investigation of nanomagnetic structures
… bulk magnon quantization in Ni nanowires: bulk spin wave quantization has been observed, and the magnon frequencies are found to decrease with increasing wire diameter. (2) investigation into the magnetic interaction between FeCo nanowires in closely-packed arrays: conclusive evidence of …
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Harnessing Magnetic Switching and Dynamics Using Electron and Magnon Spin Currents
Spintronics exploits the intrinsic spin of the electron in addition to its fundamental charge for designing next-generation electronic devices, with the purpose of reducing power consumption and enabling novel computing functions. The manipulation, transmission, and detection of spin information …
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Raman scattering studies of spinels CoV2O4 and MnV2O4
… scattering studies of the strongly correlated spinels CoV2O4 and MnV2O4. In CoV2O4, exclusive attention is given to a triply degenerate (T2g) phonon in order to determine the material's structural properties and explore coupling between the lattice and other degrees of freedom. …
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Magnetodynamics of pseudo spin valves investigated using co-planar waveguide and spin torque ferromagnetic resonance techniques
Nanocontact spin-torque nano-oscillators (NC-STNOs), based on magnetic multilayers, can generate a wide range of highly nonlinear localized and propagating spin wave modes for use in magnonics. In this thesis, we study some aspects of these structures from the fundamental physics point of view …
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Spin waves in doped graphene
Spin-waves have been studied to a great extent in solids and two-dimensional electron gases. These phenomena have garnered much interest in developing new kinds of devices for information processing and transmission. A major feature of these devices is that they would consume much less power than …
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Efficient and coherent frequency conversions and nonlinear interference in optical parametric and atomic Raman processes
… It was recently found that the atomic spin wave initially built through electromagnetically induced transparency or a weak Raman process can actively enhance the Raman frequency conversion. An experimental demonstration of an efficient Raman conversion scheme with coherent feedback of …
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Domain Wall Based Magnonics in Iron Garnet
Magnonic devices leverage magnons, quantized spin waves, as the mechanism to process and transfer information. In materials with low Gilbert damping, these spin wave-based systems enable ultra-fast operation while eliminating thermal heating and leakage currents inherent to conventional …
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Quantization of spin waves in ferromagnetic Ni80Fe20 nanoring
… using deep ultraviolet lithography and their spin dynamicsmeasured by Brillouin light scattering with the magnetic field applied along long (easy) axes of the rings. The dispersionless behavior of the spin wave modes observed reveals their standing wave nature. Two-dimensional simulations and …
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Nonlinear spin waves in magnetic thin films - foldover, dispersive shock waves, and spin pumping
Three nonlinear phenomena of spin waves and the spin Seebeck effect in yttrium iron garnet (YIG)/Pt bi-layer structures are studied in this thesis and are reported in detail in Chapters 4-7. In the fourth chapter, the first observation of foldover effect of nonlinear eigenmodes in feedback ring …
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Study of localization and correlation effects in disordered electronic systems
… susceptibility, and diffusion of charge-and spin-density fluctuations, for example. We have also investigated the effects of localization in the vicinity of magnetic instabilities on the Stoner criterion, Stoner excitations and the spin-wave mode. A macroscopic renormalization group study of …
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Spectroscopy of Two Dimensional Electron Systems Comprising Exotic Quasiparticles
… fluid at 3 ≥ v ≥ 5/2 reveals a rapid loss of spin polarization for v ≤ 3, as monitored by the intensity of the spin wave excitation at the Zeeman energy. The emergence of a continuum of low-lying excitations for v ≤ 3 reveals competing quantum phases in the second Landau level with intriguing …
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Effect of nonstoichiometry on the magnetism and ferroelectricity of Fe- and Co-substituted strontium titanate thin films
… several emerging memory technologies, including spin-wave devices and multi-state memory. Room temperature ferromagnetism and ferroelectricity are of great interest to the multiferroic and magnetoelectric community, as a key challenge in the field is engineering a material exhibiting room …
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