Multiferroic BiFeO3 thin films buffered by a SrRuO3 layer

Multiferroic BiFeO3 thin films of huge polarization have been successfully realized by using SrRuO3 as a buffer layer on a Pt/TiO2/SiO2/Si substrate. They consist of a single perovskite phase and are nearly randomly orientated, where the SrRuO3 buffer layer lowers the crystallization temperature and improves the crystallinity of BiFeO3. 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 SrRuO3-buffered Pt/TiO2/SiO2/Si substrate at higher temperatures show much improved polarization and reduced coercive field, together with a lowered leakage current. A huge remnant polarization (2P(r)) of 150 mu C/cm(2) and a coercive field (2E(c)) of 780 kV/cm were measured for the BiFeO3 film deposited at 650 degrees C.