Magnetic imaging using ultra-high-voltage cold-field-emission microscopes

Abstract Magnetic imaging with nanometer resolution is becoming important because the magnetization configuration within magnetic materials has to be controllable to that resolution in order to have an impact on various fields of technology, from low-energy computing to carbon-free transportation. Three recent topics in magnetic imaging research using ultra-high-voltage, cold-field-emission transmission electron microscopes are described in this paper: (1) determination of the local magnetic induction field (B-Field) distribution within CoFeB/Ta multilayers at 0.67-nm spatial resolution by applying a spherical aberration correction and using a pulse magnetization system, (2) three-dimensional B-Field mapping within a pillar containing a stack of Fe/Cr/Fe disks analyzed by electron holographic tomography, and (3) in-situ observation of nucleation and propagation of reverse domains within a Nd-Fe-B permanent magnet by using a magnetizing holder capable of applying a 0.5 T in-plane field.