Nonvolatile-memory current characteristics of BiFeO3 nanodots switched by applying external bias and force

In the domain structure of ferroelectric materials, the directions of polarization are diverse and uniformly separated, and the current flows along the domain wall due to the domain wall's relatively low bandgap. To control the ferroelectric domain structure of ferroelectric materials, it is possible to apply not only an external electric field but also a flexoelectric field, which is externally applied by an external force. In this study, we controlled the domain structure of BiFeO₃ nanodots using an external electric field as well as a flexoelectric field, and these BiFeO₃ nanodots showed changes in resistance depending on the domain structure and domain wall. The formation of domain walls in BiFeO₃ nanodots caused relatively low-resistance states, whereas when domain walls were removed, BiFeO₃ nanodots showed high-resistance states. The experimental results show that nonvolatile memory devices can be applied by controlling the domain wall in BiFeO₃ nanodots.