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Conduction through 71° Domain Walls in BiFeO 3 Thin Films

2011; American Physical Society; Volume: 107; Issue: 12 Linguagem: Inglês

10.1103/physrevlett.107.127601

1092-0145

S. Farokhipoor, Beatriz Noheda,

Dielectric properties of ceramics

Local conduction at domains and domain walls is investigated in BiFeO(3) thin films containing mostly 71° domain walls. Measurements at room temperature reveal conduction through 71° 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 BiFeO(3).