Reduced coercive field in BiFeO₃ thin films through domain engineering.

it also exhibits a photovoltaic effect, [ 2 ] metal-insulator transition, [ 3 ] electric modulation of conduction, [ 4 ] and terahertz radiation emission. [ 5 ] The lead-free composition and above room temperature multifunctionality make BiFeO 3 a potential material for a wide variety of applications in terms of sensors, memories, and spintronic devices. [ 6 ] The high value of ferroelectric polarization is very promising for next-generation ferroelectric random-access memory devices. However, the high value of the coercive fi eld is a major hurdle for the fabrication of practical devices. Here, we report an easy-to-perform domain engineering approach to reduce the coercive fi eld signifi cantly in BiFeO 3 thin fi lms. In general, three fundamental parameters, viz. polarization, leakage current, and applied electric fi eld encompass the domain of ferroelectric applications. A wider domain, as shown schematically in Figure 1 a , is always desired with a higher value of remnant polarization ( P r ), inverse leakage current ( J c − 1 ), and inverse coercive fi eld ( E c − 1 ). Signifi cantly higher values of remnant polarization have been reported in BiFeO 3 thin fi lms through use of lattice matched, vicinal, and different orientation substrates. [ 7–10 ] Similarly, the leakage current mechanism at macroscopic [ 11–14 ] and microscopic [ 15 ] scales have been studied with the intention of achieving reduced values. Comparatively, success in achieving lower values of the coercive fi eld has so far been limited. Most of the reports on fi lms with “enhanced” polarization and “reduced” leakage current have coercive fi elds of around 200 kV cm − 1 . The immediate consequence of such a high switching fi eld is the decomposition of BiFeO 3 into magnetite (Fe 3 O 4 ) and bismuth oxide (Bi 2 O 3 ) compounds. [ 16 ] The higher value of E c may exceed the breakdown