Orientation dependence of ferroelectric properties of pulsed-laser-ablated Bi4-xNdxTi3O12 films

Epitaxial (001)-, (118)-, and (104)-oriented Nd-doped Bi4Ti3O12 films have been grown by pulsed-laser deposition from a Bi4-xNdxTi3O12 (x=0.85) target on SrRuO3 coated single-crystal (100)-, (110)-, and (111)-oriented SrTiO3 substrates, respectively. X-ray diffraction illustrated a unique epitaxial relationship between film and substrate for all orientations. We observed a strong dependence of ferroelectric properties on the film orientation, with no ferroelectric activity in an (001)-oriented film; a remanent polarization 2P(r) of 12 muC/cm(2) and coercive field E-c of 120 kV/cm in a (118)-oriented film; and 2P(r)=40 muC/cm(2), E-c=50 kV/cm in a (104)-oriented film. The lack of ferroelectric activity along the c-axis is consistent with the orthorhombic nature of the crystal structure of the bulk material, as determined by powder neutron diffraction. (C) 2003 American Institute of Physics.