Fabrication and ferroelectric properties of BiFeO3/LaNiO3 artificial superlattice structures grown by radio-frequency magnetron-sputtering

Symmetric superlattice structures of multiferroic BiFeO3 and conductive LaNiO3 sublayers were grown on a Nb-doped SrTiO3 substrate with radio-frequency magnetron-sputtering. The formation of a superlattice structure was confirmed from the appearance of satellite lines on both sides of the main line in the X-ray diffraction pattern. X-ray measurements show that these superlattice films become subject to greater tensile stress along the c-axis and to increased compressive stress parallel to the surface plane with a decreasing thickness of the sublayer.The smaller is the thickness of the sublayer, the greater is the crystalline quality and the strain state. The hysteresis loops show a large leakage current at frequencies of 0.5 and 1 kHz; the polarization decreases with an increasing frequency.

► BiFeO3/LaNiO3 (BFO/LNO) superlattices structure was fabricated with rf sputtering.
► X-ray result shows the high quality of the BFO/LNO superlattice structures.
► The smaller is the thickness of sublayer, the greater is the crystalline quality.
► Large dc leakage and extrinsic interface effect on the shape of the hysteresis loops.