BOTTOM ELECTRODES DEPENDENCE OF FERROELECTRIC PROPERTIES IN EPITAXIAL BiFeO3/SrRuO3/SrTiO3 STRUCTURES

Abstract

ABSTRACT Ferroelectric properties of BiFeO3 (BFO) thin films epitaxially grown on SrRuO3 (SRO)/(001)SrTiO3 (STO) structure were investigated. First, bottom SRO electrodes were deposited on STO substrates by metalorganic chemical vapor deposition (MOCVD) or by sputtering. Then, BFO thin films were deposited on SRO/STO structures by chemical solution deposition. X-ray diffraction analysis showed that the SRO films deposited by both methods grew epitaxially on STO substrates as a single phase perovskite structure, but the out-of-plane lattice parameters of SRO were different, that is, they were 0.396 nm in MOCVD and 0.399 nm in sputtering. The leakage current densities were higher than 1 A/cm2 at room temperature in BFO films on both MOCVD-and sputtered-SRO, but the current density in the film on sputtered SRO decreased to 2 × 10−4 A/cm2 at 80 K. The remanent polarization of approximately 50 μC/cm2 was observed at 80 K in the BFO thin film on sputtered-SRO/STO.