Thickness-dependent dielectric and ferroelectric properties of 0.7Bi(Fe0.98Mn0.02)O3-0.3PbTiO3 thin films on stainless steel substrates

In this paper, ferroelectric films of 0.7Bi(Fe0.98Mn0.02)O-3-0.3PbTiO(3) (BFM-PT) on LaNiO3 (LNO)-coated stainless steel (SS) substrates with different thicknesses were fabricated by sol-gel process. X-Ray diffraction (XRD) patterns and Scanning electron microscopy (SEM) images reveal that such BFM-PT thin films show single perovskite structure and smooth surface without detected second phase. With the increase of film thickness, BFM-PT thin films exhibit increased maximum polarization (P-max) and dielectric constant (epsilon(r)), as well as reduced dielectric loss (tan delta) and leakage current density. The values of remanent polarization (P-r), epsilon(r) and tan delta (@ 10(3) Hz) for BFM-PT thin films with thickness of 1.2 mu m are 21.2 mu C/cm(2), 618 and 0.05, respectively. The conduction mechanism of the BFM-PT thin films at low electric field changes from space charge limited conduction (SCLC) to Ohmic conduction with the increase of film thickness. Our results indicate that BFM-PT thin films coated on SS substrates with LNO buffer layer maintain excellent dielectric and ferroelectric properties.

Automated summary

Ferroelectric films of BFM-PT were successfully fabricated on LNO-coated stainless steel substrates with different thicknesses using a sol-gel process. The films exhibited single perovskite structure, smooth surface, increased polarization and dielectric constant with thickness, and changed conduction mechanism with thickness increase, maintaining excellent dielectric and ferroelectric properties.