Imaging of symmetry-forbidden fringes with La1−xCaxMnO3 as example

It is shown (experimentally and theoretically) with La1−xCaxMnO3 as example that symmetry forbidden fringes can be easily obtained in HREM images due to symmetry breaking in the diffraction process (crystal tilt) or in the non-linear imaging process (e.g. 2 and 3 fold astigmatism, coma, beam tilt, anisotropic information limit). Given the normal imaging conditions of HREM microscopes such forbidden fringes can hardly be prevented.