Microwave Conductivity of Ferroelectric Domains and Domain Walls in Hexagonal Rare-earth Ferrite

TL;DR

This study uses nanoscale electrical imaging techniques to analyze the dielectric and conductive properties of ferroelectric domains and domain walls in hexagonal LuScFeO3, revealing that domain wall conductivity is dominated by dielectric loss from vibrations.

Contribution

It provides a unified physical model explaining local conductivity in ferroelectric domains and walls, emphasizing dielectric loss over mobile-carrier conduction.

Findings

Domain wall ac conductivity is dominated by dielectric loss from vibrations.

Surface band bending explains ferroelectric domain responses.

Enhanced domain wall conductivity is observed at the nanoscale.

Abstract

We report the nanoscale electrical imaging results in hexagonal $Lu_{0.6}Sc_{0.4}FeO_3$ single crystals using conductive atomic force microscopy (C-AFM) and scanning microwave impedance microscopy (MIM). While the dc and ac response of the ferroelectric domains can be explained by the surface band bending, the drastic enhancement of domain wall (DW) ac conductivity is clearly dominated by the dielectric loss due to DW vibration rather than mobile-carrier conduction. Our work provides a unified physical picture to describe the local conductivity of ferroelectric domains and domain walls, which will be important for future incorporation of electrical conduction, structural dynamics, and multiferroicity into high-frequency nano-devices.