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【期刊论文】Structural, dielectric, and ferroelectric properties of compositionally graded (Pb,La)
包定华, Dinghua Bao a) and Nobuyasu Mizutani Xi Yao and Liangying Zhang
,-0001,():
-1年11月30日
We report structural, dielectric, and ferroelectric properties of compositionally graded (Pb,La) TiO3 thin films on LaNiO3/SiO2/Si substrates, where all the films were prepared by the sol-gel technique. The crystalline orientation and surface morphology of the graded films were closely related to the deposition sequence of film layer. Upgraded film exhibited ~100! preferentially oriented growth, whereas downgraded film showed a randomly oriented growth, where the films with La content increasing or decreasing gradually along film thickness from the substrate to the top surface are called "upgraded" or "downgraded" films, respectively. The dielectric constants, for upgraded and downgraded films annealed at 650
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【期刊论文】Structural and electrical characteristics of chemical-solution-derived (Bi,La
包定华, Dinghua Bao, a) Te-Wei Chiu, Naoki Wakiya, Kazuo Shinozaki, and Nobuyasu Mizutani
,-0001,():
-1年11月30日
Ferroelectric (Bi,La) 4Ti3O12 (BLT) thin films with different Bi2O3 template layers were prepared on Pt/Ti/SiO2/Si substrates by a chemical-solution deposition method. The BLT films with a thin Bi2O3 bottom layer and those with a thin Bi2O3 intermediate layer had a (117) preferentially oriented growth after annealing at 750°C, while those with a thin Bi2O3 upper layer and those without a Bi2O3 template layer exhibited a high c-axis orientation. The surface morphologies changed with different preferential orientations. The electrical measurements showed that the use of Bi2O3 template layers improved significantly the P–E hysteresis loops of BLT thin films. The remanent polarization (2Pr) and coercive field (Ec) values of BLT films without a Bi2O3 template layer, with a Bi2O3 upper layer, with a Bi2O3 bottom layer, and with a Bi2O3 intermediate layer annealed at 750°C were 10.8, 29.12, 26.17, and 19.67mC/cm2; 79.0, 74.5, 75.5, and 76.3kV/cm, respectively, at an applied electric field of 350 kV/cm. The dielectric constants and dissipation factors were 184, 303, 243, and 217; 0.036, 0.044, 0.039, and 0.039, respectively, at the frequency of 100 kHz, for these BLT films without a Bi2O3 template layer, with a Bi2O3 upper layer, with a Bi2O3 bottom layer, and with a Bi2O3 intermediate layer. All the capacitors with Bi2O3 template layers showed good polarization fatigue characteristics at least up to 331010 bipolar pulse cycles and excellent retention properties up to 33104s.
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包定华, Dinghua Bao a, *, Xi Yao b, Kazuo Shinozaki c, Nobuyasu Mizutani c
Journal of Crystal Growth 259(2003)352-357,-0001,():
-1年11月30日
Pb (Zr,Ti) O3 (PZT) thin films were prepared on (111) Pt-coated Si substrates by a chemical solution deposition method using zirconyl heptanoate as zirconium source instead of commonly used zirconium alkoxides. The effects of processing conditions on the microstructure and electrical properties of the PZT thin films were investigated. The texture of the PZT thin films could be changed by selecting different heat-treatment methods. Orientation-dependent electrical properties, including dielectric constant, polarization, and coercive field, were examined. The randomly oriented PZT thin films annealed at 600C for 0.5h showed a well-defined ferroelectric hysteresis loop with a remanent polarization of 18mC/cm2 and a coercive field of 74kV/cm.
A1., Crystal structure, A3., Chemical solution deposition, B1., Perovskites, B2., Ferroelectric materials
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【期刊论文】Dielectric enhancement and ferroelectric anomaly of compositionally graded (Pb,Ca)
包定华, Dinghua Bao, a) Xi Yao, and Liangying Zhang
,-0001,():
-1年11月30日
Compositionally graded (Pb, Ca) TiO3 thin films were prepared on platinum-coated silicon substrates by a monoethanolamine-modified sol-gel technique. The crystalline orientation and surface morphology of the graded films were related to the deposition sequence of the film layer. The dielectric constants, for up-graded and down-graded films annealed at 600
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包定华, Dinghua Bao, a Xinhua Zhu, b Marin Alexe, and Dietrich Hessec
JOURNAL OF APPLIED PHYSICS 98, 014101 (2005),-0001,():
-1年11月30日
Bi, La 4Ti3O12(BLT)/Pb (Zr,Ti) O3(PZT)/(Bi,La) 4Ti3O12 trilayered ferroelectric thin films were epitaxially grown by pulsed laser deposition onto (001) SrTiO3 (STO) substrates with and without SrRuO3 (SRO) bottom electrodes. From x-ray pole figures and electron-diffraction patterns, the epitaxial relationships between BLT, PZT, SRO, and STO were identified to be BLT (001) PZT (001) SRO (001) SrTiO3 (001); BLT (110) PZT (100) SRO (100) SrTiO3 (100). Cross-sectional transmission electron microscopy investigations revealed that 90
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