Moiré Patterns in Transmission Electron Micrographs of Sub-Boundaries of Aluminium

Abstract

MOIRÉ patterns are interference fringes observed through two superposed, slightly misoriented diffraction gratings, or through two parallel gratings of slightly different spacing. When the misorientation between the gratings is very small the spacing of the moire fringes may be much greater than the grating spacing. Mitsuishi, Nagasaki and Uyeda¹ observed that the lattice in thin sheets of crystal may act as gratings to produce moiré patterns in the electron microscope. More recently, Hashimoto and Uyeda² have shown that dislocations in these crystals are revealed as dislocations in the moiré patterns, and Pashley, Menter and Bassett³ have recorded moiré patterns in specimens consisting of one metal epitaxially evaporated on to a single crystal film of another metal.