Observation of bulk Bragg-reflection using reflection high-energy electrondiffraction on Mn3O4-like films grown on MgO (001) by molecular beam epitaxy

Bulk Bragg diffraction spots are observed in the reflection high-energy ele ctron diffraction (RHEED) pattern of Mn3O4-like films, whose surfaces consi st of truncated-pyramid hillocks. The bulk Bragg diffraction spots are supe rposed on sharp streaks due to the flat top-face of the truncated pyramids. The appearance of the bulk Bragg diffraction spots is found to be critical ly dependent on the surface morphology. The incidence of the electron beam at the side facets of the truncated pyramids is found to give rise to the b ulk Bragg diffraction spots. It is found that the incident angle of the ele ctron beam with respect to the facet plane should be larger than 11 degrees to observe bulk Bragg diffraction spots from the Mn3O4-like films. In the Bragg diffraction spots, a kinematically forbidden 006 diffraction spot has been observed, which can be attributed to a dynamic diffraction effect. Ba sed upon the RHEED patterns, the crystal structure and lattice parameters o f the films are directly obtained. (C) 2000 Elsevier Science B.V. All right s reserved.