Publications Details
Relationships between ferroelectric 90{degree} domain formation and electrical properties of chemically prepared Pb(Zr,Ti)O{sub 3} thin films
For PZT films deposited on Pt coated substrates, remanent polarization is a monotonic function of thermal expansion of the substrate, a result of 90{degree} domain formation occurring as the film is cooled through the transformation temperature. PZT film stress in the vicinity of the Curie point controls 90{degree} domain assemblages within the film. PZT films under tension at the transformation temperature area-domain oriented; whereas, films under compression at the transformation temperature are c-domain oriented. From XRD electrical switching of 90{degree} domains is severely limited. Thus, formation of these 90{degree} domains in vicinity of the Curie point is dominant in determination of PZT film dielectric properties. Chemically prepared PZT thin films with random crystallite orientation, but preferential a-domain orientation, have low remanent polarization (24 {mu}C/cm{sup 2}) and high dielectric constant (1000). Conversely, PZT films of similar crystalline orientation, but of preferential c-domain orientation, have large remanent polarizations (37 {mu}C/cm{sup 2}) and low dielectric constants (700). This is consistent with single-crystal properties of tetragonally distorted, simple perovksite ferroelectrics. Further, for our films that grain size - 90{degree} domain relationships appear similar to those in the bulk. The effect of grain size on 90{degree} domain formation and electrical properties are discussed.