The switching kinetics in epitaxial ͑001͒-, ͑110͒-, and ͑111͒-oriented BiFeO 3 thin films were investigated as a function of applied field and time. It was found that the ferroelectric switching behavior obeys the Kolmogorov-Avrami-Ishibashi theory only in the high field range. The detailed behavior depends on the film orientation. A comparison with standard systems, such as epitaxial Pb͑Zr 0.2 Ti 0.8 ͒O 3 films, reveals some similarities as well as some differences. For instance, the presence

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... f 109°and 71°ferroelastic domain walls might be ruled out as the source of the decrease in switched polarization at low applied fields, in contrast to what is the case for a/c domain walls in tetragonal Pb͑Zr 0.2 Ti 0.8 ͒O 3 .