Controlled cation stoichiometry in pulsed laser deposition-grown BaTiO3 epitaxial thin films with laser fluence

We investigated effects of the laser fluence on structural and ferroelectric properties in BaTiO3 epitaxial thin films grown by pulsed laser deposition. We find that the low laser fluence causes the cation non-stoichiometry in the films. X-ray diffraction and ferroelectric hysteresis loop measurements reveal the strong impacts of the fluence-dependent cation non-stoichiometry on the structural and ferroelectric properties of the films. The ferroelectricity is observed for the films grown with the fluence larger than 1.3 J/cm2, where the cation ratio is kept close to stoichiometric. These results demonstrate that the cation stoichiometry controlled with the laser fluence plays an important role in determining the structural and ferroelectric properties in the BaTiO3 films.