Conduction through 71° DomainWalls in BiFeO3 Thin Films

Local conduction at domains and domain walls is investigated in BiFeO3 thin films containing mostly 71 degrees domain walls. Measurements at room temperature reveal conduction through 71 degrees 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 BiFeO3.