Domain Imaging of Magnetic Materials
Material Measurement Laboratory, Materials Science and Engineering Division
NIST only participates in the February and August reviews.
We use magnetic force microscopy (MFM), scanning electron microscopy (SEM), and magneto-optical indicator film (MOIF) imaging techniques as nondestructive methods to characterize magnetic domain structure in various technologically important magnetic materials such as nanocomposites, exchange springs, spin valves, ultrathin multilayer, and granular systems. Well known capabilities of MFM and SEM are complemented by a new imaging method: MOIF. The domain structure is imaged with this technique through the interaction of polarized light with a transparent magneto-optical indicator film, which is placed on top of a magnetic sample. Since the polarization of light is affected by the magneto-static field of the sample (Faraday effect), we can identify the sample’s magnetic domain structure through local changes in light polarization in the indicator film using a polarizing microscope. The MOIF method is expected to become a standard nondestructive quality control imaging technique for magnetic investigation of the next generation of magnetic sensors and storage devices. Using the above methods, we are studying static and dynamic magnetization and remagnetization processes and their relationships to thin-film characteristics and defects.