Phase contrast of spherical magnetic particles.

J Microsc

Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213-3890, U.S.A.

Published: April 1999

AI Article Synopsis

  • The paper presents analytical formulas for the phase shifts of electron waves influenced by a spherical, magnetized particle with a specific inner potential.
  • The study includes simulations using Foucault and Fresnel Lorentz techniques across various sizes and magnetic saturations of the particles.
  • The findings, particularly in experimental electron holography of nanocrystalline cobalt particles, confirm the predicted phase shifts, highlighting the effectiveness of this method.

Article Abstract

This paper derives analytical expressions for the magnetic and electrostatic phase shifts of a plane electron wave upon traversing a spherical, uniformly magnetized particle with a non-zero mean inner potential. The Aharonov-Bohm phase shift is represented in terms of dimensionless parameters. Standard Foucault and Fresnel Lorentz image simulations are presented for a range of particle sizes and saturation inductions. We discuss the detection limits of the Lorentz techniques and compare them with the sensitivity of the electron holography method. We conclude the paper with experimental holography results for nanocrystalline cobalt particles; the observed phase changes are in good agreement with the analytical predictions.

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http://dx.doi.org/10.1046/j.1365-2818.1999.00444.xDOI Listing

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