Electron Holography of Nanostructured Materials

This chapter contains an overview of the theory and applications of electron holography, a powerful technique that allows the phase shift of a high-energy electron wave that has passed through a thin sample to be measured in the transmission electron microscope (TEM). The recorded phase shift is sensitive to both the magnetic induction and the electrostatic potential within and around the specimen. The chapter begins with the theoretical basis of the off-axis mode of electron holography in the TEM. Selected applications of the technique for the quantitative measurement of magnetic fields and electrostatic potentials in nanoscale materials and devices are then described. The in situ application of external stimuli, including applied voltage, magnetic field, temperature and a gas reaction environment during the acquisition of electron holograms, is discussed. High-resolution electron holography and alternative modes of electron holography are described briefly and possible future developments and applications of the technique are outlined.