Giant Ferroelectric Polarization Beyond 150 µC/cm2 in BiFeO3 Thin Film

Ferroelectric BiFeO 3 thin films have been deposited on Pt/TiO 2 /SiO 2 /Si substrate by pulsed-laser deposition. From the X-ray diffraction analysis, the BiFeO 3 thin film consists of perovskite single-phase, and the crystal structure shows the tetragonal structure ( c / a = 1.018) with a space group P 4 m m . It is obtained that the BiFeO 3 thin film shows a well-saturated remarkably giant saturation polarization of 158 µC/cm 2 and a remanent polarization of 146 µC/cm 2 for a maximum applied voltage of 20 V at 90 K. These values of polarization are largest ever-measured in ferroelectrics.