9701740 Chamberlin This is a new proposal in which two novel experimental techniques will be utilized to investigate the dynamics of nanoscopic domains in various ferromagnetic and random magnetic systems. Nonresonant spectral hole burning (NSHB), where large magnetic field oscillations are used to selectively study the intrinsic local response, will provide insight into the constituents that comprise the net spectrum of response from bulk samples. Electron holography, using scanning transmission electron microscopy (STEM) combined with a small oscillating magnetic field, will provide images of magnetization dynamics in thin films and small structures with a resolution of 2-5 nm and sensitivity of 10-15-10-16emu. Questions to be addressed include: how does microscopic structure influence mesoscopic dynamics, how does transient local structure evolve, and how do mesoscopic magnetic domains govern macroscopic response? %%% This is a new proposal that aims at the central goal of information technology in trying to improve high-density magnetic storage. Someday, the physical size of stored bits of information will shrink into the submicron realm where thermal fluctuations significantly limit the lifetime of the memory. Magnetization dynamics involves a complex combination of microscopic, mesoscopic (medium-sized), and macroscopic processes. Two novel experimental techniques will be used to investigate these magnetization processes. Nonresonant spectral hole burning (NSHB) will provide information about the intrinsic local response of bulk samples and electron holography, using scanning transmission electron microscopy (STEM), will provide direct magnetic imaging of thin films and small structures with unmatched resolution and sensitivity. Questions to be addressed include: how does microscopic structure influence mesoscopic dynamics, how does transient local structure evolve, and how do mesoscopic magnetic domains govern macroscopic response? ***
