The crystallographic structure of gamma transition-alumina compared with the periodic antiphase boundary structure of a Ga2O3-rich Mg gallate

摘要

One of the high-temperature metastable phases found in the MgGa2O4-Ga2O3 system is the epsilon(Mg) non-stoichiometric Mg gallate. It has a one-dimensional periodic antiphase boundary (PAPB) structure based on the spinel structure. The APBs are parallel to the {310} planes and the APB vectors are of the 1/4<110> type when referred to the spinel structure. This generally leads to the existence of 12 monoclinic twin variants in the studied samples. By comparing the X-ray or electronic diffraction patterns of both phases, it will be shown that the recently discovered X transition-alumina has the same type of structure.