Study of phase transitions within alumina grown on top of CoAl (1 0 0) surface

The oxidation of CoAl(1 0 0) was investigated by means of Auger electron spectroscopy (AES), low energy electron diffraction (LEED), high resolution electron energy loss spectroscopy (HREELS), and scanning tunneling microscopy (STM). In the case of alumina grown after oxidation with 15,000 L at room temperature, the characteristic EEL spectrum, along with the sharp (2 × 1) LEED pattern observed after annealing at 1000 K, showed that a stable well-ordered θ alumina was formed. The intermediate phase was found after heat treatment at 1150 K. At higher temperatures, the formation of the α-like alumina was observed. The comparative study of as-oxidation versus subsequent annealing of amorphous alumina at high-temperatures revealed a close similarity between the structures of alumina.