Abstract
Materials characteristics and ferroelectric properties of relatively thick xPb(Ni 1/3 Nb 2/3 )O 3 -(1-x)Pb(Zr 0.52 Ti 0.48 )O 3 (x = 0.3), PNN-PZT films, which were prepared by doctor-blade tape-casting and bonding process, were investigated. The underlying substrate material was observed to influence significantly the phase constituent for the PNN-PZT layers. For the PNN-PZT/alumina films, pyrochlore phase coexists with the perovskite, whereas for the PNN-PZT/sapphire films, only pure perovskite phase was obtained, regardless of sintering temperature. The presence of pyrochlore phase markedly degrades the ferroelectric properties of the PNN-PZT layers, viz. the remanent polarization (Pr) reduces about 50 and the coercive field (E c ) increases more than 30 for the pyrochlore containing PNN/PZT/alumina films, as compared with those for pyrochlore free PNN-PZT/sapphire films. Moreover, the substrates impose pronounced constrain on materials shrinkage, inducing the formation of pores in the PNN-PZT layers. Fortunately, the pores thus found are not interconnected such that the materials still exhibit low leakage current behavior (J e 1.0 nA/cm 2 ) and large electrical polarization characteristics (Pr = 16.7 μ C/cm 2 ), with small coercive field (Ec = 12.4 kV/cm). © 2002 Taylor & Francis.