UV assisted pyrolysis of solution deposited BiFeO3 multiferroic thin films. Effects on microstructure and functional properties

BiFeO3 thin films were processed on platinized silicon substrate via chemical solution deposition. Short wave UV assisted pyrolysis was conducted in oxygen atmosphere in order to obtain a fine and homogeneous grain structure. Phase pure thin films with a pronounced (100) texture were obtained at a fairly low annealing temperature of 600°C. For comparison specimens processed without UV assisted pyrolysis were also investigated. It is shown that UV assisted pyrolysis leads to a substantial improvement of leakage resistance properties. Polarization switching could also be obtained using capacitance-voltage (C-V) curves. The leakage current was investigated as a function of temperature. Interpretation in terms of Frenkel-Poole mechanism leads to a high trap depth in the range of 2.4 eV which is attributed to the creation of Fe2+ centres. For both microstructures investigated well saturated magnetization loops were obtained with a remnant magnetization of 2Mr = 5.4 emu/cm3 and a coercive fields in the range of 2Hc = 200 Oe. Slightly higher saturation magnetization 2Ms of 55.4 emu/cm3 was obtained for UV assisted pyrolysis in comparison to 45.8 emu/cm3 for the thin films processed without UV.