Ferroelectric polarization switching kinetics process in Bi0.9La0.1FeO3 thin films

Bi0.9La0.1FeO3 (BLFO) thin films with the thickness of similar to 500 nm were deposited on (001) oriented SrTiO3 substrate with 30 nm LaNiO3 as buffer layer. The switching kinetics process of ferroelectric BLFO thin films was investigated by using pulse voltages. The result shows that one dimension and two dimensions are the prior grown modes of BLFO domains in the polarization switching process. The dimensionality of the domain growth n increases linearly with applied voltage, and the grown model varies from 1 D (n = 1, implies needlelike growth) to 2 D (n = 2, planar growth) with electric pulses increasing. This is explained due to the increase in the density of nucleating domains at high fields where sideway growth is limited. The higher value of n can be an indication of non-homogeneous distribution of domain nuclei. Under all our experimental conditions that the switching time t(sw) is instrumentally limited and therefore the intrinsic switching time of ferroelectric BLFO films is smaller than several nanoseconds. This very short polarization switching time can be explained as a switching mechanism controlled by nucleation rate. Considering the domain walls de-pinning and thermal disturbance, the saturated polarization increases with the temperature increasing under the same input voltage which in turn affects the he switching transient current and switching time. (c) 2013 AIP Publishing LLC.