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Doping of rhombohedral bismuth ferrite (BFO) with rare earth elements has been widely investigated as a pathway to extract ferromagnetic response from an otherwise antiferromagnetic material. However, increased level of such doping, in conjunction with the ability of BFO to accommodate large strain, has also resulted in nontrivial changes in the structure, i.e., transition to orthorhombic structure and phase separation to form vertically aligned columns. Herein, epitaxially grown and single crystalline samarium oxide (Sm2O3) and doped BFO films are used to investigate the structural evolution. Thin films are grown from undoped (BFO and Sm2O3) and doped targets, (0.2,0.5)Sm2O3–(0.8,0.5)BFO. In addition, the in‐plane strain, imposed by the lattice mismatch between film and substrates, is used to demonstrate the stability of the structures formed in the doped films. Interestingly, the resultant orthorhombic structures are found to be largely independent of the underlying substrates. In‐depth structural and nanoscopic measurements are conducted to investigate the structures. Ordered columnar structures, reminiscent of phase separation, are successfully obtained albeit driven by spontaneous ordering of differently oriented crystals.

We demonstrate the synthesis of self-assembled threedimensional nanocomposite thin films consisting of NiO nanocolumns in an layered Aurivillius phase matrix. The structures were grown on single-crystal SrTiO 3 substrates via pulsed laser deposition (PLD) with single ceramic (PbTiO 3 ) x (BiNi 2/3 Nb 1/3 O 3 ) 1−x targets. The nanocolumns, which are about 10 nm in diameter each, extend over the entire film thickness of up to 225 nm. We reveal the difference in electrical conduction properties of the nanocolumns and the surrounding matrix on the nanoscale via conductive atomic force microscopy. The nanocomposite thin films exhibit improved photovoltaic performance compared to both pure PbTiO 3 and homogeneous Aurivillius phase thin films.