Next-generation magnetic-memory devices and heat-assisted magnetic-recording applications\ will require a better understanding of magnetic multilayers and their interactions with optical-laser\ pulses. In this thesis, by combining the advantages of ultrabroad-band extreme-ultraviolet light\ including ultrafast time resolution, element selectivity and tabletop easy access, I report three\ findings in the study of ultrafast magnetization dynamics in itinerant ferromagnets. First, I experimentally\ prove that the transverse magneto-optical Kerr response with extreme-ultraviolet light has\ a purely magnetic origin and that our experimental technique is an artifact-free ultrafast magnetic\ probe. Second, I demonstrate the first ultrafast magnetization enhancement driven by ultrafast\ spin currents in Ni/Ru/Fe multilayers. Third, I engineer the sample system by choosing either\ insulating or spin-scattering spacer layers between the Ni and Fe magnetic layers and by structural\ ordering. Then, I control the competition between ultrafast spin-flip scattering and superdiffusive\ spin-current mechanisms; either of these processes may to be the dominant mechanism in ultrafast\ demagnetization. Finally, I report two continuing experiments that are promising for future\ ultrafast magnetization studies with extreme-ultraviolet sources. These experiments are resonant magnetic\ small-angle-scattering and the generation of bright circularly polarized high harmonics\ accompanied by a demonstration of the first x-ray magnetic circular dichroism with a tabletop\ system.
CY - Boulder, CO DA - 2014-04 N2 -Next-generation magnetic-memory devices and heat-assisted magnetic-recording applications\ will require a better understanding of magnetic multilayers and their interactions with optical-laser\ pulses. In this thesis, by combining the advantages of ultrabroad-band extreme-ultraviolet light\ including ultrafast time resolution, element selectivity and tabletop easy access, I report three\ findings in the study of ultrafast magnetization dynamics in itinerant ferromagnets. First, I experimentally\ prove that the transverse magneto-optical Kerr response with extreme-ultraviolet light has\ a purely magnetic origin and that our experimental technique is an artifact-free ultrafast magnetic\ probe. Second, I demonstrate the first ultrafast magnetization enhancement driven by ultrafast\ spin currents in Ni/Ru/Fe multilayers. Third, I engineer the sample system by choosing either\ insulating or spin-scattering spacer layers between the Ni and Fe magnetic layers and by structural\ ordering. Then, I control the competition between ultrafast spin-flip scattering and superdiffusive\ spin-current mechanisms; either of these processes may to be the dominant mechanism in ultrafast\ demagnetization. Finally, I report two continuing experiments that are promising for future\ ultrafast magnetization studies with extreme-ultraviolet sources. These experiments are resonant magnetic\ small-angle-scattering and the generation of bright circularly polarized high harmonics\ accompanied by a demonstration of the first x-ray magnetic circular dichroism with a tabletop\ system.
PB - University of Colorado Boulder PP - Boulder, CO PY - 2014 EP - 161 TI - Studying Laser-Induced Spin Currents Using Ultrafast Extreme Ultraviolet Light VL - Ph.D ER -