Conducting atomic force microscopy studies on domain wall currents of Bi₅Ti₃FeO₁₅ nanodots fabricated by anodic aluminum oxide nanotemplate and sol–gel process

We investigated the local current characteristics of Bi₅Ti₃FeO₁₅ (BTFO) nanodots on Nb-doped SrTiO₃ substrates affected by their ferroelectric domain structures and domain walls. The BTFO nanodots with a diameter of about 50 nm were fabricated by anodic aluminum oxide nanotemplates and a BTFO sol–gel process. Based on a piezoresponse force microscope, it was confirmed that domain walls were formed in the ferroelectric domain structures of the epitaxial BTFO nanodots. Current changes due to ferroelectric tunneling junctions according to ferroelectric polarizations in epitaxial BTFO nanodots were confirmed by conduction atomic force microscopy. In particular, the domain walls formed in the epitaxial BTFO nanodots formed high currents compared to the currents in ferroelectric tunneling junctions due to polarizations. Research highlights: Ferroelectric Bi₅Ti₃FeO₁₅ nanodots with a diameter of 50 nm. Ferroelectric domain structures observed with piezoresponse force microscopy. High domain wall currents observed at domain boundaries observed with conducting atomic force microscopy.