Papers by Keyword: Ferroelectric Property

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Authors: Dan Xie, Zhi Gang Zhang, Tian Ling Ren, Li Tian Liu
Abstract: {0.75SrBi2Ta2O9-0.25Bi3TiTaO9}(SBT-BTT) thin films were prepared by the modified metalorganic solution deposition (MOSD) technique. The microstructure and ferroelectric properties of SBTBTT thin films were studied. The SBT-BTT thin films were produced at 750°C. The grain size and surface roughness of SBT-BTT films showed significant enhancement with an increase in annealing temperatures. It is found that SBT-BTT thin films have good ferroelectric properties. The measured remanent polarization values for SBT-BTT, SBT and BTT capacitors were 15, 7.5 and 4.8μC/cm2, respectively. The coercive field for SBT-BTT capacitors was 50kV/cm. More importantly, the polarization of SBT-BTT capacitors only decreased 5% after 1011 switching cycles at a frequency of 1MHz.
Authors: Jai Hyun Kim, Kyung Shin Koh, Woong Kil Choo
Abstract: We have investigated the ferroelectric and electrical properties of PZT 40/60 films on the bottom La1/2Sr1/2CoO3(LSCO) electrode. The LSCO bottom electrode was sputtered on the SiO2/Si(100). As the annealing temperature of PZT capacitors on the LSCO is increased, the ferroelectric properties gradually increase with the annealing temperature up to 650°C. However, for the PZT capacitors annealed above 650°C, electrical measurement cannot be performed.
Authors: Jian Ping Yang, Xing Ao Li, An You Zuo, Zuo Bin Yuan, Zhu Lin Weng
Abstract: Bi4Ti3O12 (BTO) and Bi3.25La0.75Ti3O12 (BLT) ferroelectric thin films were deposited on Pt/Si substrates by RF magnetron sputtering with Bi4Ti3O12 (BTO) and Bi3.25La0.75Ti3O12 (BLT) targets with 50-mm diameter and 5-mm thickness. The microstructure and ferroelectric properties of thin films were investigated. The grain growth behavior and ferroelectric properties such as remanent polarization were different in these two kinds of film, the effects of La doping in the BLT thin film were very obvious.
Authors: Xing Ao Li, Zu Li Liu, An You Zuo, Zuo Bin Yuan, Jian Ping Yang, Kai Lun Yao
Abstract: Bi4-xLaxTi3O12 (BLT) ferroelectric thin films were deposited on Pt/Si substrates by RF magnetron sputtering with Bi4-xLaxTi3O12 (x=0.5, 0.75, 1) targets with 50-mm diameter and 5-mm thickness. The effects of La contents on microstructure and ferroelectric properties of Bi4-xLaxTi3O12 thin films were investigated. The grain growth behavior and ferroelectric properties such as remanent polarization were found to be dependent on the La contents in the BLT thin films.
Authors: J.H. Choi, H.S. Yoo, K.W. Cho, N.K. Kim, S.H. Oh, E.S. Choi, S.J. Yeom, H.J. Sun, S.S. Lee, K.N. Lee, Suk Kyoung Hong, Tae Whan Hong, Il Ho Kim, Sung Lim Ryu, Soon Young Kweon
Abstract: A 16Mb 1-transistor /1-capacitor (1T1C) FeRAM device was fabricated with lead-free Bi3.25La0.75Ti3.0O12 (BLT) capacitors. The key integration processes contain a scalable MTP (Merged Top-electrode and Plate-line) cell structure and reliable BLT ferroelectric capacitors. Ferroelectric properties of BLT films were optimized on the newly developed MTP cell structure. BLT films were coated on Pt/IrOx/Ir bottom electrode using sol-gel solutions. The composition of the optimized BLT film was about Bi3.25La0.75Ti3.0O12. The switchable polarization obtained in a 100nm-thick BLT film was about 20 µC/cm2 at the 3 V applied voltage, and the optimized BLT film showed a few fatigue losses about 10% up to 1 × 1011 cycles. The imprint properties of the BLT film were also characterized at 25°C and 90°C operating temperature after 125°C data storage. The average cell signal sensing margin between data "1" and data "0" was measured to be about 900 mV, which is a sufficiently large margin for device operation.
Authors: Muangjai Unruan, R. Wongmaneerung, Yongyut Laosiritaworn, Supon Ananta, Rattikorn Yimnirun
Abstract: In this work, effects of compressive stress on the ferroelectric properties of 0.7PMN–0.3PT ceramics were investigated. The ceramics with the formula (0.7)Pb(Mg1/3Nb2/3)O3-(0.3)PbTiO were prepared by a conventional mixed-oxide method. The ferroelectric properties under compressive stress were observed at stress up to 80 MPa using a compressometer in conjunction with a modified Sawyer-Tower circuit. The results showed that applied stress had a significant influence on the ferroelectric properties of 0.7PMN–0.3PT ceramics. Ferroelectric characteristics, i.e. the area of the ferroelectric hysteresis (P-E) loop, the saturation polarization (Psat), the remanent polarization (Pr) and loop squareness (Rsq), decreased with increasing compressive stress, while the coercive field (Ec) remained relatively constant. Stress-induced domain wall motion suppression and non-180oC ferroelectric domain switching processes are responsible for the changes observed.
Authors: Bo Ping Zhang, Jing Feng Li, Li Min Zhang, Jun Zeng, Yan Dong
Abstract: Lithium and titanium co-doped NiO ceramics have been found to exhibit a giant low-frequency dielectric constant (ε~105), however, the same system thin films is not yet study. In the present study, Lithium and titanium co-doped NiO thin films were prepared by a chemical solution deposition method using 2-methoxyethanol as a solvent, nickel actate tetrahydrate, lithium acetate dihydrate and titanium isopropoxide as starting materials. The complex oxides such as NiO, Ni0.2O0.8 and NiTiO3 were formed for the Ni0.98Ti0.02O and Ni0.686Li0.294Ti0.02O thin films, and the addition of the lithium lead to the formation of Li2NiO2.888. The dielectric constant of Lithium and titanium co-doped Ni0.686Li0.294Ti0.02O thin films is about 426 at 100 Hz and much higher than that of the titanium-doped Ni0.98Ti0.02O.
Authors: Piyachon Ketsuwan, Anurak Prasatkhetragarn, Supon Ananta, Chien Chih Huang, David P. Cann, Rattikorn Yimnirun
Abstract: The 3 mol% Nb2O5 doped Pb(Zr0.52Ti0.48)O3 with addition of 1-3 mol% Cr2O3 prepared via the solid-state reaction technique have been investigated. The XRD shows that a sample is primarily in both tetragonal and rhombohedral phases coexist and the amount of rhombohedral phase decreases that is due to the donor (Nb) dopant reduces the number of oxygen vacancies and leads to a lower amount of rhombohedral phase. The maximum dielectric constant tend to decrease with increasing Cr doping concentration from 0.1 to 1 mol%. Further increase in Cr concentration, the maximum dielectric constant increase dramatically. The hysteresis loop measurements, the electrical coercivity and the remnant polarization do not show a systematic trend at low concentration of Cr doping. It is possibly due to the partial solubility of Cr doping. The observations clearly indicate the hardening behavior at higher concentration because of more solubility of Cr.
Authors: Jun Bo Wu, Xin Gui Tang, Qiu Xiang Liu, Yan Ping Jiang
Abstract: (Pb1-xBax)ZrO3 (PBZ) ceramics for x = 0.10 were synthesized by the mixed oxide solid state reaction method. Phase transition was investigated by dielectric measurements in the temperature range from 27 to 350 °C at various frequencies. The permittivity of the solids corresponding to (Pb1-xBax) ZrO3 showed the maximum value of 10220 at x = 0.10 at the phase transition temperature. The maximum permittivity gradually increasing concentration up to x = 0.10. The ferroelectric hysteresis loop of the PBZ ceramics for x = 0.10 is displayed at room temperature and 0.2 Hz.
Authors: S. Marković, M. Mitrić, Č. Jovalekić, M. Miljković
Abstract: Multilayered BaTi1-xSnxO3 (BTS) ceramics with different Ti/Sn ratios were produced by pressing and sintering at 1420 oC for 2 hours. X-ray diffractometry, scanning electron microscopy and energy dispersive spectroscopy were used for structural, microstructural and elemental analysis, respectively. The dielectric and ferroelectric behavior of sintered samples was studied, too. It is found that in ingredient materials, with increasing Sn content, the tetragonality decreases; Curie temperature moves towards room temperature, while the maximum of the dielectric constant increases, and also, they becomes less hysteretic. It is noticed that multilayered BTS ceramics with different Ti/Sn contents have a broad transition temperature and show a relatively high dielectric constant in a wide temperature range. It is shown that dielectric properties of these materials may be modified by a combination of different BTS powders as well as layers number.
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