Multiferroic thin films of Ni-substituted BiFeO3 were grown by chemical-solution deposition on Pt/Ti/SiOx/Si(100) substrates. Films with up to 7.5 atom % Ni substitution showed a single perovskite phase with rhombohedral structure at room temperature, while films with 10 atom % Ni substitution showed a tetragonal-like crystal structure. Ni substitution of 2.5 atom % was effective in suppressing leakage current in the high-electric-field region with high polarization (72 mu C/cm(2)) and coercive field (340 kV/cm) when polarization vs electric field hysteresis loops were drawn at 20 kHz with a maximum electric field of 1100 kV/cm. (C) 2008 The Electrochemical Society.