Influence of multi-ion co-doping and NiFe2O4 layer on the properties of BiFeO3/NiFe2O4 composite films by sol-gel

Pure BiFeO3 (BFO), BiFeO3/NiFe2O4 (BFO/NFO) and multi-ion co-doped Bi0.89Sm0.11Fe0.34Mn0.04Cr0.02O3/NiFe2O4 (BSFMC/NFO) thin films have been synthesized by using a sot-gel method. The influences of multi-ion co-doping and NFO layer co-doping on its crystalline structural, leakage current and multi-ferroic properties are investigated. The results indicate that an asymmetry of J-E curves at negative and positive applied electric fields is clearly observed in the BFO/NFO and BSFMC/NFO films, which is apparently related to the effects of the interface between the BFO and NFO layers. Moreover, improved ferroelectric and ferromagnetic properties are observed in the BSFMC/NFO film simultaneously, e.g. large remanent polarization and saturation magnetization is 66.18 mu C/cm(2) and 34.20 emu/cm(3), respectively. (C) 2014 Elsevier B.V. All rights reserved.