Very large spontaneous electric polarization in BiFeO3 single crystals at room temperature and its evolution under cycling fields

Electric polarization loops are measured at room temperature on highly pure $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_3$ single crystals synthesized by a flux growth method. Because the crystals have a high electrical resistivity, the resulting low leakage currents allow the authors to measure a large spontaneous polarization in excess of $100\mu \mathrm{C}{\mathrm{cm}}^{-2}$ , a value never reported in the bulk. During electric cycling, the slow degradation of the material leads to an evolution of the hysteresis curves eventually preventing full saturation of the crystals.