The Condensed Matter & Surface Sciences Colloquium Series presents Zheng Gai of Oak Ridge National Laboratory on “Growth and Properties of Magnetic Nanostructures and Thin Films,” on Thursday, April 7, at 4:10 p.m. in Walter 245.
Zheng Gai
Abstract: The main topic of this presentation is about the investigation of the consequences of spatial confinement on spin structure, and spin dynamics. New properties that emerge at the nanoscale have at least three origins. First, as the surface to volume ratio increases, material properties are increasingly dominated by surface and interface effects. Secondly, spatial confinement results in new quantum phenomena. The oscillatory exchange coupling, GMR, spin tunneling, and exchange bias manifest in magnetic multilayers are linked with one or both of these factors. Finally, spatial confinement will enhance correlation effects. Surface and interface effects modify moment sizes, exchange interactions, anisotropy energies, and modes of electron transport. These changes affect the spin structure (moment size and order, non-collinear magnetism), spin dynamics (spin wave dispersion and lifetime, switching modes and times, moment stability at finite temperature and phase transitions, quantum tunneling), and spin transport (disorder and spin-flip scattering, channeling, quantum conductance, spin current-driven changes in moments). The richness of magnetism in nanostructured materials arises from the interplay between all of these effects. Uncovering and exploiting these interrelationships in different classes of materials requires a concerted research effort involving novel synthesis, advanced characterization, and innovative theory and modeling. This presentation will talk about the controlled growth, characterization and physics properties of several interesting magnetic systems.
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