Ferroelectric polarization-controlled resistive switching in BaTiO3/SmNiO3 epitaxial heterostructures

Abstract

As an emerging phenomenon in oxide heterostructures, the ferroelectric control of electronic transport is attracting considerable research attention. However, the effect of ferroelectric polarization on resistive switching (RS) remains controversial. In this study, to determine the effects of ferroelectric polarization on memory characteristics, ferroelectric and non-ferroelectric BaTiO3 (BTO) films were fabricated using different oxygen partial pressures (Po2) during film growth. A correlated electron oxide, SmNiO3 (SNO), was selected as the bottom electrode. Based on piezoelectric force microscopy, ferroelectricity was verified in the BTO films prepared at Po2 ≥ 3 Pa, whereas the films fabricated at lower Po2 did not exhibit ferroelectricity. Remarkable RS with an ON/OFF ratio of 104% was clearly observed in heterostructures containing ferroelectric BTO, while RS was negligible in structures with non-ferroelectric BTO. The strong ferroelectricity dependence of RS behavior on the BTO/SNO heterostructures was attributed to the ferroelectric control of device transport between bulk-limited current in the low-resistance state and interface-limited conductance in the high-resistance state, which results from the modulation of the potential barrier at the BTO/SNO interface. The findings provide strong evidence for the dominant effect of ferroelectric polarization of BTO on the transport properties of BTO/SNO heterostructures.