  We have explored the influence of deposition pressure and temperature on the
growth of BiFeO3 thin films by pulsed laser deposition onto (001)-oriented
SrTiO3 substrates. Single-phase BiFeO3 films are obtained in a region close to
10-2 mbar and 580C. In non-optimal conditions, X-ray diffraction reveals the
presence of Fe oxides or of Bi2O3. We address the influence of these parasitic
phases on the magnetic and electrical properties of the films and show that
films with Fe2O3 systematically exhibit a ferromagnetic behaviour, while
single-phase films have a low bulk-like magnetic moment. Conductive-tip atomic
force microscopy mappings also indicate that Bi2O3 conductive outgrowths create
shortcuts through the BiFeO3 films, thus preventing their practical use as
ferroelectric elements in functional heterostructures.
