Electrical and magnetic properties of multiferroic BiFeO3/CoFe2O4 heterostructure

To realize a magnetoelectric heterostructure with desired ferroelectric and magnetic properties, a heterostructure consisting of BiFeO3 (BFO)/CoFe2O4 (CFO) layers has been grown on SrRuO3 buffered Pt/TiO2/SiO2/Si substrate by rf sputtering. X-ray diffraction shows that the BFO and CFO phases have been successfully retained in the heterostructure. Grain growth of the CFO phase was enhanced on top of the BFO layer. The heterostructure exhibits both ferroelectric and magnetic behaviors at room temperature. Its remanent polarization (2Pr) is measured to be ∼146 μC/cm2 and the coercive field (2Ec) is ∼1803 kV/cm, while the saturation magnetization (2Ms) is 140 emu/cm3 and the coercive field (2Hc) is ∼2.7 kOe. The leakage current behavior of the heterostructure is consistent with space charge limited conduction mechanism. While the heterostructure is promising for multiferroic behavior, it would be necessary to control the structural defects such that the leakage is minimized.