Multiferroic BiFeO ₃ Thin Films Buffered by a SrRuO ₃ Layer

Abstract

Multiferroic BiFeO 3 thin films of huge polarization have been successfully realized by using SrRuO 3 as a buffer layer on a Pt/TiO 2 /SiO 2 /Si substrate. They consist of a single perovskite phase and are nearly randomly orientated, where the SrRuO 3 buffer layer lowers the crystallization temperature and improves the crystallinity of BiFeO 3 . With increasing deposition temperature during magnetron sputtering, they undergo an apparent grain growth and reduction in surface roughness. The multiferroic thin films deposited on the SrRuO 3 ‐buffered Pt/TiO 2 /SiO 2 /Si substrate at higher temperatures show much improved polarization and reduced coercive field, together with a lowered leakage current. A huge remnant polarization (2 P r ) of 150 μC/cm 2 and a coercive field (2 E c ) of 780 kV/cm were measured for the BiFeO 3 film deposited at 650°C.