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 5 at.% Sm exhibited a single perovskite phase with rhombohedral structure, whereas films with 7.5 and 10 at.% Sm exhibited a distorted orthorhombic crystal structure. Atomic force microscopy of the films showed homogeneous and smooth surface. Films with 7.5 at.% 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 100 nm thick film with 3 V coercive voltages. Moreover, well saturated P-E hysteresis loops with high polarization (80 mu C/cm(2)) and low coercive field (300 kV/cm) were also recorded in 100 nm thick films with low coercive voltage (5 V). The Sm-substitution in BiFeO3 improved the fatigue endurance with no significant degradation in polarization even after 10(8) fatigue cycles. These results demonstrate that Sm-substituted BifeO(3) films have potential for application in low voltage operational device. (C) 2012 Elsevier B. V. All rights reserved.