Structural and Ferroelectric Properties of Domain-Structure-Controlled BiFeO3 Thin Films Prepared by Dual-Ion-Beam Sputtering

BiFeO3 (BFO) thin films have been grown on vicinal SrTiO3 (STO) < 001 > substrates by dual-ion-beam sputtering. The Bi/Fe composition ratio was optimized by adjusting the beam current ratio of a dual-ion beam. The domain structure was controlled using a vicinal STO substrate along < 100 > and < 110 >. From the results of X-ray diffraction analysis and piezoelectric force microscopy, it is found that BFO thin films grown on vicinal STO along < 100 > and < 110 > show stripe and single-domain structures, respectively. It is found that the reduction in the length of non-180 degrees domain walls improves leakage current characteristics, resulting in an enhancement of ferroelectric D-E characteristics. The single-domain BFO thin film shows excellent D-E hysteresis loops at room temperature, with a double remanent polarization (2P(r)) and a double coercive field (2E(c)) of 140 mu C/cm(2) and 340 kV/cm, respectively. (C) 2012 The Japan Society of Applied Physics