Electrical conduction mechanism in BiFeO3-based ferroelectric thin-film capacitors: Impact of Mn doping

• Conduction properties of BiFeO3 and 10% Mn-doped BiFeO3 thin films are investigated.
• A switchable diode effect is observed only for the BiFeO3 films.
• The BiFeO3 films show a space-charge-limited current conduction.
• The Mn-doped BiFeO3 films retain ohmic conduction under a high applied voltage.
• The Mn-doping reduces a depletion layer width adjacent to electrode/BiFeO3 interfaces.

Electrical conduction properties of SrRuO3(SRO)/BiFeO3(BFO)/SRO and SRO/10% Mn-doped BFO(BFMO)/SRO ferroelectric thin-film capacitors are investigated. The BFO capacitors exhibit a switchable diode effect accompanied by a conduction change from ohmic to space-charge-limited current with increasing external field. In contrast, the BFMO capacitors show only an ohmic conduction, arising from a considerable reduction in depletion layer width at the SRO/BFMO interfaces. These results suggest that the diode property can be tuned by Mn content in the BFO film. Our study opens the possibility of controlling the diode effect in BFO-based devices by a dilute Mn doping.