Large anisotropy of ferroelectric and dielectric properties for Bi3.15Nd0.85Ti3O12 thin films deposited on Pt/Ti/SiO2/Si -: art. no. 222901

Polycrystalline Bi3.15Nd0.85Ti3O12 (BNdT) thin films of a-axis preferential orientation [alpha((100))=62%] and high c-axis orientation [alpha((001))=96%] were fabricated directly on Pt/Ti/SiO2/Si substrates through a sol-gel process. We observed strong dependences of ferroelectric and dielectric properties on the film orientation, with a remanent polarization 2P(r) of 39 mu C/cm(2) and dielectric constant epsilon(r) of 343 at 100 kHz in the a-axis oriented film; 2P(r) of 20 mu C/cm(2) and epsilon(r) of 331 in the film of random orientation; and 2P(r) of 13 mu C/cm(2), epsilon(r) of 218 in the highly c-axis oriented film. Furthermore, the 2P(r) value of a purely a-axis-oriented BNdT film can be predicted to be similar to 51 mu C/cm(2). The large anisotropy of 2P(r) and epsilon(r) values demonstrates that the polarization vector of BNdT is close to the a axis. (c) 2005 American Institute of Physics.