Structural and electrical properties of Sm-substituted BiFeO3 thin films prepared by chemical solution deposition

The structural and electrical properties of chemical-solution-deposited Bi1−xSmxFeO3 (x=0, 0.025, 0.05, 0.075, 0.1) thin films on Pt/Ti/SiOx/Si (100) substrates were investigated. Films up to 5at.% Sm exhibited a single perovskite phase with rhombohedral structure, whereas films with 7.5 and 10at.% Sm exhibited a distorted orthorhombic crystal structure. Atomic force microscopy of the films showed homogeneous and smooth surface. Films with 7.5at.% Sm exhibited significant reduction in leakage current in the high electric field region and improved breakdown characteristic. The polarization vs. electric field (P–E) hysteresis loops were recorded in a 100nm thick film with 3V coercive voltages. Moreover, well saturated P–E hysteresis loops with high polarization (80μC/cm2) and low coercive field (300kV/cm) were also recorded in 100nm thick films with low coercive voltage (5V). The Sm-substitution in BiFeO3 improved the fatigue endurance with no significant degradation in polarization even after 108 fatigue cycles. These results demonstrate that Sm-substituted BifeO3 films have potential for application in low voltage operational device. ► The electrical properties of Sm-substituted BiFeO3 thin films are investigated. ► Leakage current reduced and improved breakdown characteristic. ► Polarization-electric field hysteresis loops recorded with 3V coercive voltages. ► Improved fatigue endurance with no significant degradation in Pr after 108cycles. ► These films have potential for applications in low voltage operational devices.