A study of enhanced memory effect in PZ/PZT multilayer thin films (in PZ/PZT series sequences) prepared by sol-gel technique

Lead Zirconate (PbZrO3 : PZ) and Lead Zirconium Titanate (PZT) multilayered thin films were prepared by sol-gel technique. Sets of films (each layer has a 500 angstrom thickness) made by one PZ after one PZT layer are deposited 3 times successively, so it contains 3 PZ layers and 3 PZT layers. We measured EFM images of theses films after applying voltages of 2, 4, 6, 8 and 10 volts respectively at different areas to check whether the polarization reversals can be detectable or not after 30 minutes. The polarization mark was observed clearly at 10 volt applied area. As the applied voltages were going down the polarization marks also were diminishing down. Polarization reversal could be hardly seen in 4 volt written area and could not observe the mark in 2 volt written area. It is clear that the multilayered films had superior memory effects to normal PZT films by comparing the EFM images that were prepared with the same methods.