Electric properties of Sm doped bismuth ferrite-based thin film and its resistive switching behavior for memristor

Bismuth ferrite is a multi-functional material with many unique properties especially for nanoscale thin films, which can be used in the integrated, miniaturized devices, and muti-functionalization applications. The highquality Sm-doped 0.78BiTi0.1Fe0.8Mg0.1O3-0.22CaTiO3 (Sm-BTFM-CTO) thin films were fabricated by sol-gel method on Pt/Ti/SiO2/Si substrate. Then the influence of Sm doping contents on the properties of piezoelectricity, ferroelectricity, and dielectricity were analyzed. The structural and compositional characterization results confirmed the successful element doping and ferroelectric phase structure of thin films. The atomic force microscopy (AFM) and piezoresponse force microscopy (PFM) results revealed that the thin film had smaller grain size and excellent piezoelectric properties as Sm content is 4 %. The first and second harmonic PFM and lithoPFM results proved the intrinsic piezoresponse and room temperature ferroelectric properties. As a result, the 4 % Sm-BTFM-CTO thin film exhibited excellent piezoelectricity, stable room temperature ferroelectricity with a relatively large maximum polarization (81.98 mu C/cm2), high dielectric constant (297.16), small dielectric loss (about 0.0523) and low leakage current density (1.59 x 10-9 A/cm2). In conclusion, this work demonstrated that appropriate Sm doping can improve the electrical performance. And the Sm-BTFM-CTO-based memristor was prepared to study its characteristics including current-voltage (I-V) curves, resistance switching, on/off ratio behaviors. And the variation of conductivity under different voltage was characterized systemically to understand the characteristics of memristor. These studies provide a simple pathway for preparing high-quality multiferroic BFO-based films by sol-gel method and promote the application of the ferroelectric hardware in memristor devices.