Conduction through 71o domain walls in BiFeO3 thin films

TL;DR

This study investigates conduction mechanisms at 71° domain walls in BiFeO3 thin films, revealing that both domain and domain wall conduction are governed by similar processes involving defect states and Schottky emission, with implications for oxide electronics.

Contribution

It demonstrates conduction through 71° domain walls in BiFeO3 thin films and elucidates the mechanisms governing conduction in both domains and walls, advancing understanding of oxide conduction pathways.

Findings

Conduction occurs at 71° domain walls at room temperature.

Both domains and walls share similar conduction mechanisms involving defect states and Schottky emission.

Oxygen vacancies influence the Fermi energy and Schottky barrier locally.

Abstract

Local conduction at domains and domains walls is investigated in BiFeO3 thin films containing mostly 71o domain walls. Measurements at room temperature reveal conduction through 71o domain walls. Conduction through domains could also be observed at high enough temperatures. It is found that, despite the lower conductivity of the domains, both are governed by the same mechanisms: in the low voltage regime electrons trapped at defect states are temperature-activated but the current is limited by the ferroelectric surface charges; in the large voltage regime, Schottky emission takes place and the role of oxygen vacancies is that of selectively increasing the Fermi energy at the walls and locally reducing the Schottky barrier. This understanding provides the key to engineering conduction paths in oxides.