C-AXIS ORIENTED FERROELECTRIC SRBI2(TAXNB2-X)O-9 THIN-FILMS

c-Axis oriented SrBi2(TaxNb2-x)O-9 (SBTN) ferroelectric thin films (0 < x < 2) have been deposited, for the first time, using pulsed laser a blation. Films were stoichiometries close to the target composition we re deposited successfully on MgO(100)/Pt(100) substrates. X-ray diffra ction analysis of the films showed a predominant (00l) orientation wit h small amounts of (115) and (200) orientations. The c-axis orientatio n was introduced primarily by choosing(100) Pt as the substrate materi al which has a lattice spacing close to the lattice parameter a (basal plane) in the pseudo-tetragonal unit cell of the layered structure fe rroelectric material. The orientation effect is also attributed to the high energy of the depositing species, which is characteristic of the laser ablation process. The films show very good ferroelectric proper ties at room temperature and no fatigue up to 10(9) cycles. For exampl e, SBTN films with a composition close to x = 0.8 show a remnant polar ization value of 11 mu C cm, a coercive field of 45 kV cm(-1) and a re sistivity of 4 x 10(13) Omega cm. Comparison of these values with thos e obtained from films with no preferred (00l) orientation indicate a s ignificant drop in the coercive field by 20 kV(-2) cm(-1) and an incre ase in resistivity by an order of magnitude in the c-axis oriented fil ms.