Characteristics of Undoped and Mn-Doped BiFeO3 Films Formed on Pt and SrRuO3/Pt Electrodes by Radio-Frequency Sputtering

Pure BiFeO3 (BFO) and Mn-doped BiFeO3 (BFMO) films were deposited at 550 °C on Pt(111) and SrRuO3(SRO)/Pt(111) bottom electrodes using radio-frequency (RF) sputtering. Mn doping of 5 at. % into BFO films was effective in reducing leakage current density at a high electric field. In polarization versus electric field (P–E) measurement at 100 kHz, square hysteresis loops were obtained at room temperature in both BFO and BFMO films on Pt and SRO/Pt electrodes. In the BFMO films, the frequency dependence of the remanent polarization was not pronounced, even when the measurement frequency was decreased to 5 kHz. In the BFO film, on the other hand, no accurate hysteresis loops could be measured at a frequency below 10 kHz, because of the large leakage current.