In this paper, we report evidence of ferroelectricity in perovskite manganite (BiMnO3) thin films synthesized via r.f. magnetron
sputtering method on a single-crystal (1 0 0)-oriented SrTiO3:Nb 0.1% and Pt/TiO2/SiO2/Si substrates. X-ray diffraction measurements
were used to analyse the crystal structure of the thin films, revealing epitaxial growth for BiMnO3 films with their (1 1 1) and (2 2 2) planes
parallel to the (0 0 1) and (0 0 2) planes of the SrTiO3 substrate. AFM measurements were performed to investigate surface morphology;
quantitative values of roughness and grain size are in the range between 300 and 500 nm. Ferroelectric characterization was conducted at
low temperatures and at 300 K. Hysteresis loops (polarization vs. voltage) were obtained, showing saturation polarizations of 40 nC=cm2,
and 25nC=cm2 at 105, 122, and 300 K. Resistance vs. temperature measurements were performed, which indicated this to be very robust
insulating material. |
