Spin Wave Solitons, Fractals, and Fermi-Pasta-Ulam Recurrence in Magnetic Films
Carl E. Patton
Department of Physics, Colorado State University, Fort Collins, CO
Date: April 20, 2007, Time: 3:30 pm, Location: W122-D3 Engineering Building 1, The University of Houston
Abstract:
Solitons are ubiquitous to many physical systems. These include shallow and deep water waves, nonlinear electrical circuits, fiber optics, and Bose Einstein condensates. The nonlinear and dispersive spin wave properties in magnetic thin films and the ready availability of extremely low loss single crystal films of yttrium iron garnet (YIG) make this an ideal model system for the study of envelope solitons. This talk will present a comprehensive yet tutorial overview of work at Colorado State University on microwave magnetic envelope (MME) solitons in YIG film waveguides. Be prepared to think about wave packets, linear and nonlinear, in ways you probably have never thought about them before.
The talk will cover the following topics: I. Solitons and envelope solitons - what is a soliton; some history; some pictures. II. Soliton basics - nonlinearity; chirp and dispersion compensation, the nonlinear Schrödinger equation. III. Spin waves in magnetic thin films - the spin wave soliton experiment, YIG films, spin waves, linear eigenmodes, the dispersion D and nonlinearity N in thin films. IV. Microwave magnetic envelope solitons - pulse driven bright solitons, higher order solitons, phase, thresholds, decay, dark solitons. V. YIG film feedback rings and other special effects - soliton trains, solitons as natural nonlinear eigenmodes, cloning and trapping, modulational instability, fractals, and Fermi-Pasta-Ulam recurrence.
Work supported in part by the Office of Naval Research, Grant N00014-06-1-0889, and the U. S. Army Research Office, Grant W911NF-04-1-0247.
Brief Biography of Carl E. Patton
Dr. Patton is Professor of Physics at Colorado State University (CSU), Fort Collins, Colorado. He received his Bachelor of Science degree in physics from the Massachusetts Institute of Technology, Cambridge, Massachusetts, and his Master of Science and Ph.D. degrees in electrical engineering from the California Institute of Technology, Pasadena, California. He is currently on sabbatical at Seagate Research Laboratory, Pittsburgh, Pennsylvania. His research group at CSU is involved in magnetics research on bulk and thin film hexagonal ferrite materials, metallic films, microwave and millimeter wave relaxation processes, Brillouin light scattering, ferromagnetic resonance, nonlinear spin wave processes, and spin wave solitons, chaos, and fractals. Dr. Patton is a Life Fellow of the IEEE and a Life Fellow of the American Physical Society. He was awarded an IEEE Third Millennium Medal and has received an IEEE Magnetics Society Lifetime Achievement Award. He has served as Reviews Editor and Editor-in-Chief of the IEEE Transactions on Magnetics, as a General or Publication Chair for several international magnetism conferences, and as an IEEE Magnetics Society Distinguished Lecturer. He was the first elected chair of the American Physical Society Topical Group on Magnetism and its Applications. He is a member of the International Organizing Committee for the International Conference on Ferrites. He is presently serving as the President of the IEEE Magnetics Society.
