Nanoscale study of perovskite BiFeO3/spinel (Fe,Zn)3O4 co-deposited thin film by electrical scanning probe methods

For this study, a BiFeO3 (BFO) perovskite/(Fe,Zn)3O4 (FZO) spinel sample grown on SrTiO3:Nb (0 0 1) has been prepared using pulsed laser deposition with a single target composition of (Bi1.1FeO3)0.65(Fe2.2Zn0.8O4)0.35. The nanoscale electrical properties of ferroelectric BFO/semi-conducting FZO thin film have been investigated using piezoresponse force microscopy (PFM) and conductive-atomic force microscopy (C-AFM). Scanning probe methods reveal that BFO grows as nano-islets with a complex structure which is coherent with the cross-sectional high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images. The comparison between nanoscale electrical techniques and HAADF-STEM images have allowed to understand the origin of the different physical properties of the multiferroic/magnetoconductive co-deposited thin film at the nanoscale. By using PFM/C-AFM techniques, we were able to fully distinguish BFO and FZO materials in the nanostructured sample without using destructive material characterization methods.