Giant ferroelectric polarization beyond 150 μC/cm2 in BiFeO3 thin film

Ferroelectric BiFeO3 thin films have been deposited on Pt/TiO2/SiO2/Si substrate by pulsed-laser deposition. From the X-ray diffraction analysis, the BiFeO3 thin film consists of perovskite single-phase, and the crystal structure shows the tetragonal structure (c/a = 1.018) with a space group P4mm. It is obtained that the BiFeO3 thin film shows a well-saturated remarkably giant saturation polarization of 158 muC/cm(2) and a remanent polarization of 146 muC/cm(2) for a maximum applied voltage of 20 V at 90 K. These values of polarization are largest ever-measured in ferroelectrics.