2.3 Microstructure

Depending on the process, perovskite type ceramics show a great variety of microstructures. These structures vary from epitaxial films to fine grained polycrystalline. Apart from perfect epitaxial films, structures that are epitaxial only perpendicular to the substrate surface are quite common. In this case the grain boundaries cross the entire film, thus leading to a columnar microstructure.

Typical grain sizes vary between 3 and 100$\mathrm{\mu}$m for conventional titanate ceramics and 10 to 100nm for fine grained thin films [Die97].