Features of the (0001) Supersmooth Surface Structure of Magnetoplumbite-Like LaMgAl11O19 Single Crystals

Abstract

Single crystals of LaMgAl₁₁O₁₉ with the magnetoplumbite-type structure are grown from the melt. They demonstrate a perfect cleavage in the (0001) plane. According to atomic force microscopy, the surface of the fresh (0001) cleavage of LaMgAl₁₁O₁₉ single crystals is characterized by an extremely low roughness (R_z < 0.05 nm), which is typical for pure atomically smooth crystal faces without steps. The annealing of LaMgAl₁₁O₁₉ single-crystal plates in air at 1200°C results in recrystallization and significant morphological changes in the surface, namely, the formation of flat triangular or hexagonal prisms with strictly parallel sides and dimensions in the plane (0001) up to 0.5 μm and different heights (0.7 and 1.8 nm).