Microstructure evolution of Bi0.4Ca0.6MnO3 epitaxial films with different thickness

Bi0.4Ca0.6MnO3 (BCMO) film was epitaxially grown on a (1 1 0) SrTiO3 substrate using the pulsed laser ablation technique. The morphologies of the epitaxial films with different thicknesses were considerably different. For the Bi0.4Ca0.6MnO3 epitaxial film with a thickness of 10 nm, the morphology was more like islands. As the film thickness increased to 40 nm, the island became smaller, and disappeared when the film thickness reached 110 nm. The growth mechanism of the epitaxial films depends on film thickness, which has been discussed. The results will shed light on the formation mechanism of BCMO epitaxial films.