Defect-related room-temperature ferroelectricity in tensile-strained SrTiO3 thin films on GdScO3 (110) substrates

We investigate room-temperature (RT) ferroelectricity in tensile-strained SrTiO3 (STO) thin films grown on GdScO3 (110) substrates. To separate the strain and the defect dipole effect, we apply an electric field to measure the polarization in the direction perpendicular to the elongation axis, and the RT ferroelectric polarization is found to be perpendicular to that axis. These results clearly demonstrate the importance of the contribution of defect dipoles to the RT ferroelectricity observed in STO thin films.