Multiferroic behaviour and orientation dependence of lead-free (1 - X)BiFeO3-x(Bi0.50Na0.50)TiO3 thin films

Abstract

Lead-free multiferroic (1 - x)BiFeO3-x(Bi0.50Na 0.50)TiO3 (BFOBNTx) thin films were deposited by off-axis radio frequency magnetron sputtering on SrRuO3 buffered SrTiO 3 (1 1 1), SrTiO3 (1 0 1), SrTiO3 (1 0 0) and LaAlO3 (0 0 1) substrates. Their ferroelectric behaviour is strongly dependent on the film composition and orientation. 0.95BiFeO3-0. 05(Bi0.50Na0.50) TiO3 (BFOBNT5) exhibits notably better ferroelectric behaviour and fatigue endurance than the films of other compositions. The largest spontaneous polarization occurs in its (1 1 1) direction, where a remanent polarization of 2Pr ∼ 198.3 νC cm-2 is measured, while the polarizations in other directions are consistent with the projections from the (1 1 1) direction. © 2009 IOP Publishing Ltd.