Keywords: ferroelectric films, nanoscale investigations, thin films, piezoresponse force microscopy, local piezoelectric hysteresis loops, domain imaging, switching properties, coercive voltage, piezoelectric activity, nanotechnology
Nanoscale investigations of switching properties and piezoelectric activity in ferroelectric thin films using piezoresponse force microscopy
With respect to nanoscale ferroelectric thin films research, piezoresponse force microscopy (PFM) for domain imaging and local piezoelectric spectroscopy for switching properties and piezoelectric activity measurements require the control of experimental conditions associated to the experimental set-up. To avoid any misinterpretation of the results, stiffness of the cantilever, or frequency and amplitude of the driving AC voltage have to be carefully investigated. In this paper, optimal working conditions determined with our experimental set-up are described in order to evidence the architecture of domains, to measure the coercive voltage and to evaluate the piezoelectric activity of Pb(Zr, Ti)O3 thin films. Illustrations are carried out on highly oriented, unetched and ion beam etched tetragonal films; explanations of the behaviour of the ferroelectric material at the nanoscale level are given.