Electron Phase Counting Micromagnetometry Using a Differential Phase Contrast/Interference Scanning Transmission Electron Microscope

Abstract

A new method of micromagnetometry, electron phase counting (EPC), using a scanning transmission electron microscope with differential phase contrast and interference imaging modes has been proposed and tested. By counting the relative phase changes occurring in a pair of mutually coherent fine probes as they are moved from an observation point to a nearby reference point, integrated magnetic flux density at the observation point can be quantified without recourse to instrumental signal intensity calibration. Its feasibility for practical micromagnetometry has been confirmed by the successful application of two different EPC procedures to a NiFe alloy film.

Lorentz And Interference Electron Microscopy On A Scanning Tem

“…The signals therefore suffice to generate integrated in-plane magnetic induction maps (Fig.2). 2 Furthermore, by making use of the fact that the Lorentz deflection distribution across the image plane forms an irrotational (vortex-free) 2D vector field, a pertinent numerical image processing yields a function equivalent to the electron phase function representing magnetically distorted electron wavefront. In its contour map, flux lines are delineated if the magnetic induction is confined two-dimensionally (Fig.3).…”

Quantification of local remanence magnetization in perpendicular magnetic recording film by scanning interference electron microscopy

“…[4][5][6] We have shown previously that scanning interference electron microscopy, which is based on the interference between two focused electron probes, can be used to obtain absolute induction magnitude from an image. 7,8 The variation of the integrated magnetic induction, i.e., the magnetic flux, across the area enclosed by the two probes induces a change in the electron phase difference between the probes. As this relative phase change can be transformed into image contrast that varies periodically with a unit of h/e ͑h: Planck's constant, e: electron charge͒, a quantitative magnetic image can be obtained.…”