Effect of domain structure on dielectric nonlinearity in epitaxial BiFeO3 films

Rayleigh analysis has been used to investigate dielectric nonlinearity in epitaxial (001)-oriented BiFeO3 films with engineered domain structures from single-to four-variant and stripe domain samples with 71 and 109 domain walls. Single-domain variant films display minimal irreversible contributions, whereas the ratio of irreversible to reversible contributions increases by approximately one order of magnitude as the number of variants increases to two-and four-variants, respectively. These measurements indicate that the density of domain walls and degree of domain wall complexity influence the number and strength of domain wall pinning sites. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3533017]