Lorentz image-derived film media noise

Noise from thin-metal-film media is derived directly from Lorentz electron microscope images of the micromagnetic domain structure. In this first attempt to extract quantitative information from such images, Fe-Co-Cr alloy, a medium that is more easily interpretable than many others, is selected. For initial simplicity, noise from a bulk AC-erased disk is the focus of this analysis, rather than transition noise. A flux-noise spectrum is obtained from an image by processing and is compared with the same noise spectrum measured through a thin-film head flying over the disk.>