We report the synthesis and characterization of ferroelectric lead zirconate titanate Pb͑Zr 0.53 Ti 0.47 ͒O 3 (PZT) nanowires. The PZT nanowires, with diameters of about 45 nm and lengths of about 6 m, were fabricated by means of a sol-gel method utilizing nanochannel alumina templates. After postannealing at 700°C, the PZT nanowires exhibit a polycrystalline microstructure, and x-ray diffraction and transmission electron microscopy study revealed their perovskite crystal structure. Recently, increasing efforts have been made to synthesize and understand ferroelectric nanostructures because of the promise they show in the realization of nanoscale piezoelectric transducers and actuators, ultrasonic devices, and nonvolatility memory devices. [1][2][3][4][5] As ferroelectricity represents a cooperative phenomenon that relies on the interaction of neighboring permanent electric dipoles in a crystal lattice, there is a size limit, known as the superparaelectric limit, below which ferroelectricity vanishes. Therefore, the synthesis of ferroelectric nanostructures of a controllable size and shape is of great interest not only for future applications but also from a fundamental point of view. Urban and coworkers have reported earlier the synthesis of BaTiO 3 and SrTiO 3 nanorods with diameters ranging from 5 to 60 nm by a solution-phase decomposition of bimetallic alkoxide precursors in the presence of coordinating ligands.6 Using a sol-gel template method of synthesis, Hernandez et al. have fabricated BaTiO 3 and PbTiO 3 nanotubes within 200 nm alumina templates.7 Some interesting properties have also been found in ferroelectric nanowires. For example, BaTiO 3 nanowires as small as 10 nm in diameter still retain ferroelectricty, and nonvolatile polarization domains as small as 100 nm 2 in size can be induced on BaTiO 3 nanowires. This suggests that ferroelectric nanowires may be used to fabricate nonvolatile memory devices with an integration density approaching 1 terabit/ cm 2 . 8Lead zirconate titanate Pb͑Zr 0.53 Ti 0.47 ͒O 3 (PZT) is a ferroelectric material that possesses a perovskite crystal structure, and shows a high potential for applications in device due to its high dielectric constant, high Curie temperature, and high breakdown strength. PZT nanotubes have been obtained within silicon and nanochannel alumina (NCA) templates by using several different deposition techniques, including misted chemical solution deposition and pore wetting. 3,9 In this letter, we report the synthesis of the PZT nanowires by using a sol-gel template method. We choose NCA as the template because the pore diameters of the NCA template can be well controlled from several hundreds of nanometers to 5 nm. Ferroelectric properties have been demonstrated in individual PZT nanowires by using piezoresponse force microcopy (PFM).NCA templates were prepared by means of anodization, 10,11 and the PZT nanowires were synthesized by sol-gel method utilizing the NCA templates. A PZT sol-gel precursor was prepared according to a previous report, 12...

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The resistive switching (RS) characteristics of flexible films deposited on mica substrates have rarely been reported upon, especially flexible HfO2 films. A novel flexible Au/HfO2/Pt/mica resistive random access memory device was prepared by a sol-gel process, and a Au/HfO2/Pt/Ti/SiO2/Si (100) device was also prepared for comparison. The HfO2 thin films were grown into the monoclinic phase by the proper annealing process at 700 °C, demonstrated by grazing-incidence X-ray diffraction patterns. The ratio of high/low resistance (off/on) reached 1000 and 50 for the two devices, respectively, being relatively stable for the former but not for the latter. The great difference in ratios for the two devices may have been caused by different concentrations of the oxygen defect obtained by the X-ray photoelectron spectroscopy spectra indicating composition and chemical state of the HfO2 thin films. The conduction mechanism was dominated by Ohm’s law in the low resistance state, while in high resistance state, Ohmic conduction, space charge limited conduction (SCLC), and trap-filled SCLC conducted together.

Sodium bismuth titanate, (Na0.5Bi0.5)TiO3 (NBT), thin films were grown on Pt/Ti/SiO2/Si substrates via a sol−gel process. The precursor solution for spin-coating was prepared from bismuth nitrate, sodium acetate, and titanium n-butoxide as starting materials, and acetic acid and methanol as solvents, and pervoskite NBT films with high (111)-orientation have been obtained. The Au/NBT/Pt thin film capacitor showed a hysteresis loop at an applied electric field of 200 kV/cm with remanent polarization (P r) and coercive electric field (E c) values of 20.9 μC/cm2 and 112 kV/cm, respectively. At 100 kHz, the dielectric constant and loss tan δ of the film were 171 and 0.024, respectively. The leakage current depended on the voltage polarity. When an electrical field ranges from 0 to 167 kV/cm and with the Pt electrode biased negatively, the NBT/Pt interface exhibits a Schottky emission characteristic. The Au/NBT interface forms an ohmic contact. The conduction current when the Au electrode is biased negatively shows space-charge-limited current (SCLC) behavior.