Spectroscopic ellipsometry of NiO and Co$_{\mathrm{\mathbf{3}}}$\textbf{O}$_{\mathrm{\mathbf{4}}}$\textbf{ thin films with different orientations grown on SrTiO}$_{\mathrm{\mathbf{3}}}$\textbf{ substrates by polymer-assisted deposition}

NiO and Co$_{\mathrm{3}}$O$_{\mathrm{4}}$ films exhibit various interesting properties, such as excellent chemical stability, antiferromagnetic ordering and low light absorption. These properties have rendered them for potential application in protective coatings, electrochromic windows and nonvolatile resistance random access memory devices. NiO and Co$_{\mathrm{3}}$O$_{\mathrm{4}}$ films have been prepared by a number of techniques, including pulsed laser deposition, sputtering, atomic layer deposition and sol-gel method. We have prepared epitaxial NiO and Co$_{\mathrm{3}}$O$_{\mathrm{4}}$ thin films with different orientations (001), (110), (111) grown on three orientations of single crystal SrTiO$_{\mathrm{3}}$(001), (110), (111) substrates by a solution method, called polymer-assisted deposition. Analyses from x-ray diffraction revealed the epitaxial relationship between the films and the substrates. Atomic force microscope showed that those films have very smooth surface with rms surface roughness less than 1 nm. Their optical properties were investigated by spectroscopic ellipsometry.