Ferroelectric properties of Sr2Bi4Ti5O18 thin films

Bi-based layered ferroelectric thin films of Sr2Bi4Ti5O18 (SBTi) were prepa red by pulsed-laser deposition. The c-axis-oriented SBTi films were grown o n SrRuO3 seeded Pt/TiO2/SiO2/Si substrates while polycrystalline SBTi films were grown on Pt/TiO2/SiO2/Si substrates. The measurements of ferroelectri city revealed that the direction of spontaneous polarization was not along the c axis since the polarization of c-axis-oriented films was much less th an that of randomly oriented films. There was no significant degradation of switchable charge at least up to 10(11) cycles for the randomly oriented f ilms, suggesting that, even with Ti which was widely accepted to contribute to the fatigue of Pb(Zr, Ti)O-3, SBTi showed superior fatigue characterist ics. The randomly oriented films also showed excellent retention characteri stics after 10(5) s. (C) 2000 American Institute of Physics. [S0003-6951(00 )04021-3].