Top electrode induced self-polarization in CSD processed SBT thin films.

The CSD processed Strontium Bismuth Tantalate (SBT) ferroelectric films presents a certain degree of self-polarization when no further annealing after sputtered Pt top electrode deposition is performed. Using the measurement of the first pulsed hysteresis loop the percentage of switchable self-polarized polarization is quantitatively analyzed. Pyroelectric coefficient measurements assess the validity of the results obtained. The hysteresis loop measurements indicate that the polarization vector points to the bottom electrode. When the top electrode is a Hg drop instead of Pt, the degree of self-polarization obtained is different both in magnitude and sign. These results are explained as a competition between the self-polarization induced by the top and bottom platinum electrodes.