Intermediate multidomain state in single-crystalline Mn-doped BiFeO thin films during ferroelectric polarization switching.

A intermediate multidomain state and large crystallographic tilting of 1.78° for the (hh0) planes of a (001)-oriented single-domain Mn-doped BiFeO (BFMO) thin film were found when an electric field was applied along the [110] direction. The anomalous crystallographic tilting was caused by ferroelastic domain switching of the 109° domain switching. In addition, ferroelastic domain switching occurred via an intermediate multidomain state. To investigate these switching dynamics under an electric field, we used in situ fluorescent X-ray induced Kossel line pattern measurements with synchrotron radiation. In addition, in situ inverse X-ray fluorescence holography (XFH) experiments revealed that atomic displacement occurred under an applied electric field. We attributed the atomic displacement to crystallographic tilting induced by a converse piezoelectric effect. Our findings provide important insights for the design of piezoelectric and ferroelectric materials and devices.