Variation of electric properties across the grain boundaries in BiFeO<inf>3</inf> film

Abstract

Stark differences in charge transport properties between the interior and the boundary regions of grains in an undoped BiFeO3 thin film have been found. The material is ferroelectric and each grain is a single domain. A spatial resolution that distinguishes between the grain interior and the boundary between the grains has been achieved by using piezoelectric force microscopy and conductive atomic force microscopy measurements. The local electric properties, as well as the local band gap show hysteresis only when probed in the grain interior, but do not show hysteresis when probed in the region around the boundary between two grains. The leakage current is more pronounced at the grain boundaries, and the region that carries significant current increases with the applied voltage.