Study on ferroelectric domains in BaTiO3 crystalline films and bulk crystals by atomic force and scanning electron microscopies

We have observed cylindrical 180 degrees domains and 90 degrees multi-domains in crystalline films by an atomic force microscope and in bulk crystals by a scanning electron microscope. The size distribution of the 180 degrees domain end is determined graphically by a computer analysis. A discussion is given on why a thickness dependence of the end size coincides with the theoretical relation proportional to the square root of the thickness over a wide range from 4 nm to 1.4 mm and why the 90 degrees domain is found only in a film of a particular thickness. (C) 1998 American Institute of Physics. [S0021-8979(98)06514-1].