Imaging ferroelectric domains with soft X-ray ptychography at the oxygen K-edge

TL;DR

This paper demonstrates a novel imaging technique using soft X-ray ptychography at the oxygen K-edge to visualize ferroelectric domains in BiFeO₃ films, revealing detailed domain structures and ferroic contributions.

Contribution

The study introduces the use of ptychographic dichroic imaging at the O K-edge for high-resolution visualization of ferroelectric domains, extending capabilities to multiferroic oxides.

Findings

Visualized ferroelectric domains in BiFeO₃ with high contrast.

Identified hybridization effects at the O K-edge.

Complemented magnetic imaging at Fe L₃-edge.

Abstract

The ferroelectric domain structure of a freestanding BiFeO$_3$ film was visualized by ptychographic dichroic imaging with linearly polarized X-rays at the O K-edge around 530 eV. The dichroic contrast is maximized at the energy of the hybridization of the O 2p state and the Fe 3d orbitals, which is split by the octahedral crystal field of the perovskite structure. The microscopy images thus obtained complement the ptychographic imaging of the antiferromagnetic contribution at the Fe L$_3$-edge. The approach can be extended to the separation of different ferroic contributions in other multiferroic oxides.