Quantitative micromagnetics: electron holography of magnetic thin films and multilayers

A new method for the absolute measurement of magnetic microstructure at nanometer spatial resolution in magnetic materials has been developed by implementing off-axis electron holography in a scanning transmission electron microscope (STEM). The holography modes permit quantitative measurement of magnetic induction and magnetization, the determination of equimagnetization lines in domains and straightforward determination of domain wall and flux vortex profiles. STEM holography accompanied by the conventional techniques has been applied to the characterisation of thin magnetic films, magnetic multilayer structures and small magnetic particles. This combination of micromagnetic analysis techniques in one instrument provides a valuable tool for the investigation of magnetic microstructure and microscopic structure in magnetic materials with high sensitivity (/spl sim/10/sup -15/ emu) and at nm spatial resolution.