Polycrystalline BiFe_(1-x)Mn_(x)O_(3) films with x up to 0.50 are prepared on LaNiO3 buffered surface oxidized Si substrates.The doped Mn is confirmed to be partially in a+4 valence state.A clear exchange bias effect is observed with a 3.6 nm Ni_(81)Fe_(19) layer deposited on the top BiFe_(1-x)Mn_(x)O_(3) layer,which decreases drastically with increasing Mn doping concentration and finally to zero when x is above 0.20.These results clearly demonstrate that the exchange bias field comes from the net spins due to the canted antiferromagnetic spin structure in polycrystalline BiFe_(1-x)Mn_(x)O_(3) films,which transforms to a collinear antiferromagnetic spin structure when the Mn doping concentration is larger than 0.20.
Bipolar resistive switching is studied in BiFe0.95Zn0.05O3 films prepared by pulsed laser deposition on （001） SrTiO3 substrate, with LaNiO3 as the bottom electrode, and Pt as the top electrode. Multiple steps of resistance change are ob- served in the resistive switching process with a slow voltage sweep, indicating the formation/rupture of multiple conductive filaments. A resistive ratio of the high resistance state （HRS） to the low resistance state （LRS） of over three orders of mag- nitude is observed. Furthermore, the conduction mechanism is confirmed to be space-charge-limited conduction with the Schottky emission at the interface with the top Pt electrodes in the HRS, and Ohmic in the LRS. Impedance spectroscopy demonstrates a conductive ferroelectric/interfacial dielectric 2-layer structure, and the formation/rupture of the conductive filaments mainly occurs at the interfacial dielectric layer close to the top Pt electrodes.
