Ferroelectric properties of Bi3.6Ho0.4Ti3O12 thin films prepared by sol-gel method

The Ho-substituted bismuth titanate [(Bi3.6Ho0.4Ti3O12), (BHT)] thin films were prepared on Pt∕Ti∕SiO2∕Si substrates by sol-gel method. The microstructure and electrical properties were investigated. The BHT film consists of a single phase of Bi-layered Aurivillius structure. The surface is uniform, smooth, crack-free, and with a dense microstructure. The 600-nm-thick film exhibits 2Pr of 44.2μC∕cm2 and 2Ec of 323.7kV∕cm at 500kV∕cm. After the switching of 4.46×109cycles, the BHT film shows fatigue-free (only 3% degradation). The dielectric constant and dielectric loss are about 489 and 0.018 at a frequency of 1MHz, respectively. The BHT film shows good insulating behavior according to the test of leakage current.