Kg. Brooks et al., INFLUENCE OF TEXTURE ON THE SWITCHING BEHAVIOR OF PB(ZR0.70TI0.30)O-3SOL-GEL DERIVED THIN-FILMS, Journal of materials research, 12(2), 1997, pp. 531-540
Rhombohedral Pb(Zr0.70Ti0.30)O-3 thin films of four different well-def
ined textures, namely, (100), (111), bimodal (110)/(111), and (100)/(1
11), were prepared by a sol-gel method. The films were characterized i
n terms of grain size, presence of second phases, surface roughness, c
olumnarity of grains, and other microstructural features. The dielectr
ic, ferroelectric, and fatigue properties were investigated, with emph
asis on the hysteresis switching characteristics. Results are discusse
d from the reference point of the allowable spontaneous polarization d
irections available for the different textures. The values of coercive
held, remanent and saturation polarization, and slope of the loop at
the coercive held, at saturating fields can be qualitatively explained
based on the texture, independent of microstructural differences. The
occurrence of surface pyrochlore, however, is observed to affect the
functionality of the saturation curves, particularly for the samples o
f bimodal texture. Shearing of the hysteresis curves of the bimodal fi
lms is also attributed to surface microstructural features. The occurr
ence of nonswitching 71 degrees or 109 degrees domains in the (111) an
d (110)/(111) textured films is hypothesized based on a comparison wit
h the data from the (100) textured film. Corrected saturation polariza
tion values agree with the spontaneous polarization values of rhombohe
dral PZT single crystals and published calculated Values for rhombohed
ral PZT ceramics. The fatigue characteristics show increases in the sw
itching component of polarization in the range 10(3)-10(7) bipolar cyc
les, particularly for the (111) textured sample. Onset of fatigue is o
bserved for all samples between 10(7) and 10(8) switching cycles.