Scaling behavior of ferroelectric hysteresis loop in pulsed-laser-deposited SrBi2Ta2O9 thin film

Ferroelectric SrBi2Ta2O9 thin films were grown on a highly oriented Pt/Ti/SiO2/Si substrates using pulsed laser ablation. The hysteresis loop of ferroelectric SrBi2Ta2O9 was studied as a function of applied field amplitude. A scaling analysis of ferroelectric hysteresis loop area showed Aproportional toE(alpha). The value of scaling exponent, alpha=0.40, is not similar to the reported theoretical and experimental values. This result shows the possibility that both ferroelectric bulk and thin-film systems may have different universal behaviors. Influence of potential in the surface of SrBi2Ta2O9 thin film was measured in the dc applied field range from 0 to 8 V by using electro force microscopy. Roughness of surface potential of SrBi2Ta2O9 thin film changed rapidly around the coercive voltage, V(c)similar to1.5 V. It is believed that the switching effect of SrBi2Ta2O9 thin film includes surface polarization at the surface of the thin film as well as pure spontaneous polarization in the bulk. (C) 2003 American Institute of Physics.