Effects of rare earth Nd and (Ag, Ni and In) ions codoping on the structural, electrical, optical, ferroelectric and magnetic properties of the BiFeO3 (BFO) thin films prepared on FTO/glass substrates by using a sol-gel method were investigated. From X-ray diffraction and Raman scattering analyses, distorted rhombohedral perovskite structures were observed for all the films. The X-ray photoelectron spectroscopy analysis was carried out to investigate the chemical states and lattice deficiencies of the films. Both charge states 3+ and 2+ of Fe ions are simultaneously present in all the films but 2+ state appears to be dominant. The leakage mechanisms of the films were systematically investigated by two kinds of bulk-limited conductions (space-charge-limited conduction and Poole-Frenkel emission) and two kinds of interface-limited conductions (Schottky emission and Fowler-Nordheim tunneling). The optical measurement showed that all the films have a conspicuous absorption in the blue and green light region with the band gap values around 2.7 eV. The present work reveals that the non-magnetically active Ag and In ions are more helpful than the magnetically active Ni ion in enhancing the macroscopic magnetization of BFO by the introduction of a local ferromagnetic coupling rather than an antiferromagnetic one. (C) 2013 Elsevier B.V. All rights reserved.