Sr/Bi ratio effects for Sr/sub x/Bi/sub y/Ta/sub 2/O/sub 9/ grown by pulsed laser ablation

In this study we report the effect of variations in the Sr/Bi ratio on the properties of thin film strontium bismuth tantalate (SBT), one of the primary candidates for ferroelectric nonvolatile memories. The composition was varied according to the formulation Sr/sub 1-z/Bi/sub 2.1+2/3z/Ta/sub 2/O/sub 9/. Films were prepared by pulsed laser ablation from ceramic targets. The largest switched polarizations were measured for compositions with z=0. Results are compared to other studies where off-stoichiometric compositions yielded the largest polarizations. In attempting to reduce the processing temperatures, moderate ferroelectric properties were achieved at 650/spl deg/C.