Microstructure and ferroelectric properties of low-fatigue epitaxial, all (001)-oriented (Bi,La)4Ti3O12/Pb(Zr0.4Ti0.6)O3/(Bi,La)4Ti3O12 trilayered thin films on (001) SrTiO3 substrates -: art. no. 014101

(Bi,La)(4)Ti3O12(BLT)/Pb(Zr,Ti)O-3(PZT)/(Bi,La)(4)Ti3O12 trilayered ferroelectric thin films were epitaxially grown by pulsed laser deposition onto (001) SrTiO3 (STO) substrates with and without SrRuO3 (SRO) bottom electrodes. From x-ray pole figures and electron-diffraction patterns, the epitaxial relationships between BLT, PZT, SRO, and STO were identified to be BLT(001)vertical bar vertical bar PZT(001)vertical bar vertical bar SRO(001)vertical bar vertical bar SrTiO3(001); BLT[110] vertical bar vertical bar PZT[100]vertical bar vertical bar SRO[100]vertical bar vertical bar SrTiO3[100]. Cross-sectional transmission electron microscopy investigations revealed that 90 degrees ferroelectric domain boundaries lying on 11101 planes are present in the PZT layer, with an average domain width of 20 nm and an average spacing of 120 nm. These long 90 degrees ferroelectric domains, as a rule having nucleated at the bottom of the PZT layer, extend to the top of the latter. The thin films have sharp BLT/PZT interfaces and a very flat surface. The remanent polarization and coercive field were determined as 13.9 mu C/cm(2) and 72.9 kV/cm, respectively, indicating that the epitaxial, all (001)-oriented trilayered thin films have rather good ferroelectric properties, although single epitaxial (001)-oriented BLT films are usually not favored for application due to their very poor ferroelectric properties. The thin films showed a high fatigue resistance at least up to 10(10) switching pulse cycles, confirming that such a trilayered structure effectively shows the fatigue-free behavior of BLT. (c) 2005 American Institute of Physics.