Monodomain to polydomain transition in ferroelectric PbTiO3 thin films with La0.67Sr0.3MnO3 electrodes

TL;DR

This study investigates how ferroelectric PbTiO3 thin films transition from monodomain to polydomain states as their thickness decreases, revealing size-dependent structural and polarization changes using advanced characterization techniques.

Contribution

It provides new insights into the size effects and domain structure evolution in ultrathin ferroelectric films with La0.67Sr0.3MnO3 electrodes.

Findings

Decreased c/a ratio with reduced film thickness

Recovery of c/a ratio at very small thicknesses

Transition from monodomain to polydomain polarization configuration

Abstract

Finite size effects in ferroelectric thin films have been probed in a series of epitaxial perovskite c-axis oriented PbTiO3 films grown on thin La0.67Sr0.33MnO3 epitaxial electrodes. The film thickness ranges from 480 down to 28 A (7 unit cells). The evolution of the film tetragonality c/a, studied using high resolution x-ray diffraction measurements, shows first a decrease of c/a with decreasing film thickness followed by a recovery of c/a at small thicknesses. This recovery is accompanied by a change from a monodomain to a polydomain configuration of the polarization, as directly demonstrated by piezoresponse atomic force microscopy measurements.