The static configuration of ferroelectric domain walls was investigated using atomic force microscopy on epitaxial PbZr0.2Ti0.8O3 thin films. Measurements of domain wall roughness reveal a power law growth of the correlation function of relative displacements B(L) ~ L^(2zeta) with zeta ~ 0.26 at short length scales L, followed by an apparent saturation at large L. In the same films, the dynamic exponent mu was found to be ~ 0.6 from independent measurements of domain wall creep. These results give an effective domain wall dimensionality of d=2.5, in good agreement with theoretical calculations for a two-dimensional elastic interface in the presence of random-bond disorder and long range dipolar interactions.
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