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

The Ho-substituted bismuth titanate [(Bi(3.6)Ho(0.4)Ti(3)O(12)), (BHT)] thin films were prepared on Pt/Ti/SiO(2)/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 2P(r) of 44.2 mu C/cm(2) and 2E(c) of 323.7 kV/cm at 500 kV/cm. After the switching of 4.46x10(9) cycles, 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 1 MHz, respectively. The BHT film shows good insulating behavior according to the test of leakage current. (c) 2007 American Institute of Physics.