Place : IRIG/SPINTEC, auditorium 445 CEA Building 10.05 (presential access to the conference room at CEA in Grenoble requires an entry authorization. Request it before January 27th at admin.spintec@cea.fr)
video conference : https://univ-grenoble-alpes-fr.zoom.us/j/98769867024?pwd=dXNnT3RMeThjYStybGVQSUN0TVdJdz09
Meeting ID: 987 6986 7024
Passcode: 025918
Abstract : Angular momentum transfer in all forms contributes to the loss of information carried by dynamical spin polarisations and constitutes an important fundamental problem in spintronics. In this talk, we present a detailed microwave spectrum measurement of magnetic excitations in an Yttrium Iron Garnet disk, and how one can make sense of the multitudes of spectral lines and their magnetic field dependence theoretically. We explain how the axial symmetry of the setup leads to labelling of modes in terms of the conserved total angular momentum of the spin waves, The frequency spectrum in the saturated state is compared to analytical solutions for pure exchange as well as pure dipolar models under certain limits where different types of spectral degeneracy occur. The experimental result shows splittings of those degenerate modes, and we discuss possible interpretations in relation to angular momentum transfer between its different forms.
Biography : biography: Kei Yamamoto is a theoretical physicist working on theoretical and mathematical aspects of understanding dynamical properties of magnetic materials, leveraging his background in high energy physics. He received his PhD in General Relativity and Cosmology from the Department of Applied Mathematics and Theoretical Physics, University of Cambridge, UK, and currently works as an Assistant Principal Researcher in Advanced Science Research Center, Japan Atomic Energy Agency.
bibliography : https://www.webofscience.com/wos/author/record/OGR-4892-2025