Structural Features of Pseudomorphic Spinel-Structure Films on R-Sapphire Substrates

摘要

A suspension of submicron ZnO crystallites in acetone is applied to epi-ready R(102) sapphire plates with dimensions of similar to 10 x 10 x 0.5 mm. The composite is dried and annealed in air in a tube furnace at 1200 degrees C for 60 min. According to the data of electron and scanning probe microscopy, X-ray and electron diffraction, thin oriented ZnAl2O4 zinc spinel films are formed on the sapphire substrate with the mutual orientation of lattices following the epitaxial relationships: (311)ZnAl2O4||(102)Al2O3; < 332;ZnAl2O4||< 110; Al2O3; < 110 >;ZnAl2O4||< 101 > Al2O3. Due to the relatively high synthesis temperature of the films (1200 degrees C) and the most intense cathodoluminescence of the film in the near-infrared (IR) spectrum, the formation of normal zinc spinel can be assumed. The obtained ZnAl2O4 films with the (311)-plane orientation parallel to the R plane of the sapphire substrate are supposed to be used to grow magnetic NiFe2O4 and CoFe2O4 films having the (311) plane with an easy-axis magnetization anisotropy oriented along the < 311 > direction.