Following Strain-Induced Mosaicity Changes of Ferroelectric Thin Films by Ultrafast Reciprocal Space Mapping

TL;DR

This study uses ultrafast x-ray diffraction to observe how strain-induced mosaicity affects the structural dynamics of ferroelectric PZT thin films, revealing coupling between out-of-plane expansion and in-plane lattice changes.

Contribution

It introduces a novel application of time-resolved reciprocal space mapping to study strain-induced mosaicity changes in ferroelectric thin films.

Findings

Coupling of out-of-plane expansion to in-plane lattice dynamics observed

Mosaic structure influences ultrafast structural responses

Distinct behavior between expansion and compression events

Abstract

We investigate coherent phonon propagation in a thin film of ferroelectric PbZr0.2Ti0.8O3 (PZT) by ultrafast x-ray diffraction (UXRD) experiments, which are analyzed as time-resolved reciprocal space mapping (RSM) in order to observe the in- and out-of-plane structural dynamics simultaneously. The mosaic structure of the PZT leads to a coupling of the excited out-of-plane expansion to in-plane lattice dynamics on a picosecond timescale, which is not observed for out-of-plane compression.