Nanoscopic observation of bistable piezoresponse, polarization retention, and domain imaging of sub-50 nm-thick (Pb,La)(Zr,Ti)O3 thin films

Nanoscopic characterization of the local ferroelectricity by piezoresponse measurements with scanning probe microscope is performed on a 40 nm-thick (Pb,La)(Zr,Ti)O3 (PLZT) (8/65/35) thin film prepared on a Nb-SrTiO(001) substrate. The microscopic piezoresponse showed a nearly linear dependence on the DC bias voltage with a slight bistability. The poled structure showed rapid retention. We attribute the bistability observed in the piezoresponse and the vanishing of the poled structure to a phase transition between the relaxor phase and the field-induced ferroelectric phase. The control and imaging of the local domain structure are also performed.