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1.
《Current Applied Physics》2015,15(11):1332-1336
A CaBi4Ti4O15 (CBTO) ceramic in which the Bi2O3 concentration was controlled from 0 to 10 wt% was fabricated using a solid-state reaction method. Structural analysis by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) indicated differences in the preferred grain orientation and size of the plate-like grains according to the Bi2O3 concentration. The orientation of plate-like grains was also found to vary with the Bi2O3 concentration. There was no noticeable change trend of dielectric properties with different Bi2O3 concentrations. Relatively low dielectric constants (about 135) were exhibited by the CBTO ceramic with 1 wt% Bi2O3 and CBTO ceramic with 10 wt% Bi2O3 only, and similar values (about 150) were exhibited by the other ceramics. The dielectric loss exhibited a low value in the range of 0.01–0.09 for all samples (frequency range of 1–100 kHz). Regarding the ratio changes of the piezoelectric coefficient (d33) and the ratio of a-axis orientation of plate-like grains, the trends of these two values were shown to be similar. These results suggest that the addition of Bi2O3 greatly influences the microstructure of CBTO ceramics, including the grain size and orientation of plate-like grains. In particular, the change in the preferred grain orientation is closely related to the change in the piezoelectric properties. 相似文献
2.
Effect of amorphous TiO2 buffer layer on the phase formation of CaBi4Ti4O15 ferroelectric thin films
K. Kato K. Suzuki K. Tanaka D. Fu K. Nishizawa T. Miki 《Applied Physics A: Materials Science & Processing》2005,80(4):861-864
Amorphous buffer layers of TiO2 were introduced between CaBi4Ti4O15 thin films and Pt bottom electrodes through chemical solution deposition techniques. Several tens of nanometers thick alkoxy-derived TiO2 layers were found to be critical for acceleration of the phase transition in the thin films. Unlike thin film crystallized directly onto a highly (111) oriented Pt bottom electrode, the thin film on an amorphous TiO2 layer was almost single phase perovskite and showed random orientation. The crystallinity of the CaBi4Ti4O15 thin film was much higher than that crystallized directly onto the Pt bottom electrode. The dielectric and ferroelectric properties of the CaBi4Ti4O15/TiO2 stacked thin films on Pt coated Si substrates are evaluated, leading to the potential of the amorphous buffer layer for the integrated devices being clarified. PACS 77.84.-s; 68.37.-d; 81.15.-z 相似文献
3.
CaCu3Ti4O12 (CCTO) thin films have been prepared by a pulsed-laser-deposition method on LaNiO3 buffered Pt/Ti/SiO2/Si substrates, and their microstructure and dielectric properties have been compared with those of the films deposited directly on Pt/Ti/SiO2/Si substrates. The crystalline structure and the surface morphology of the CCTO thin films were markedly affected by the bottom electrodes. Both the films show temperature-independent dielectric properties in a wide temperature range, which is similar to those properties obtained in single-crystal or epitaxial thin films, while the room-temperature dielectric constant of the 350-nm-thick CCTO films on LaNiO3/Pt/Ti/SiO2/Si substrates at 100 kHz was found to be 2300, which was increased significantly compared with that obtained in the films on Pt/Ti/SiO2/Si substrates. Using the impedance spectroscopy technique, it has been suggested that the high dielectric constant response of the CCTO thin films originates from the grain boundary layer mechanism as found in internal barrier layer capacitors. PACS 77.55.+f; 81.15.Fg; 68.55.-a 相似文献
4.
Among Aurivillius layer-structured materials, CaBi2Nb2O9 is a best potential candidate for ultrahigh-temperature applications because of its highest Curie temperature of about 940 °C. In this paper, (1-x)CaBi2Nb2O9-xBaZr0.2Ti0.8O3 composite ceramics were prepared by conventional solid-state sintering method. The dielectric results show that the introduction of BaZr0.2Ti0.8O3 not only increases the permittivity of the material, but also reduces its dielectric loss. The optimum electrical properties were obtained in the x = 0.01 sample with piezoelectric coefficient (d33) of 15.1 pC/N and high ferroelectric remnant polarization (Pr) of 9.9 μC/cm2. Furthermore, the composite samples show good thermal depoling performance, the d33 of the x = 0.01 sample is 13.8 pC/N, which is about 91% of the initial value after depoling at 800 °C. Therefore, (1-x)CaBi2Nb2O9-xBaZr0.2Ti0.8O3 is one of the candidates for high temperature piezoelectric materials. 相似文献
5.
Dalhyun Do Jin Won Kim Sang Su Kim 《Applied Physics A: Materials Science & Processing》2012,108(2):357-361
Ferroelectric La- and V-co-doped Na0.5Bi4.5Ti4O15 (NLBTV) thin film was prepared on Pt(111)/Ti/SiO2/Si substrates by using a chemical solution deposition method and annealed at 750?°C under oxygen atmosphere. Crystal structure of the thin film was investigated by X-ray diffraction and Raman scattering. Surface morphology of the thin film was investigated by scanning electron microscopy. The NLBTV thin film capacitor exhibited better ferroelectric properties such as larger remnant polarization and smaller coercive electric field than Na0.5Bi4.5Ti4O15 (NBT) thin film capacitor. Reduced leakage current was observed in the NLBTV thin film capacitor compared to the NBT thin film capacitor. Almost no polarization fatigue was observed up to 1.44×1010 switching cycles. 相似文献
6.
Barium-modified strontium bismuth titanate ceramics with chemical formula Sr1?xBaxBi4Ti4O15 (x = 0.00, 0.02, 0.06, 0.08 and 0.1) (SBBT) have been prepared by means of solid-state reaction technique and their structural and electrical properties were investigated. X-ray diffraction data confirm that all the compositions show orthorhombic structure without any deleterious phase. Scanning electron micrographs show plate like grain morphology with random orientation of platelets. The temperature-dependent dielectric study shows that the phase transition temperature decreases, but the dielectric constant increases with increase in Ba content. Complex impedance plots show that both grain and grain boundary effect on the resistance mechanisms in all the compositions. The values of the activation energy confirm that the oxygen vacancies play an important role in the conduction. The ac conductivity of SBBT ceramics increases as a function of frequency due to relaxation phenomenon which arises due to mobile charge carriers. 相似文献
7.
用传统的固相烧结工艺,制备了钼掺杂铁电陶瓷样品SrBi4Ti4O15(SBTi)铁电陶瓷SrBi4-2x/3Ti4-xMoxO15(x=0.00,0.003,0.012,0.03,0.06,0.09).X射线衍射的结果表明,样品均为单一的层状钙钛矿结构相,Mo掺杂未改变SBTi的晶体结构.通过扫描电子显微镜观测发现,样品晶粒为片状,随掺杂量的增加,晶粒逐渐变小.铁电测量表明,Mo掺杂使SBTi的铁电性能得到较大改善.随掺杂量x的增加,样品的剩余极化(2Pr)呈现出先增大,后减小的规律.在x=0.06时,2Pr达到最大值26.5 μC/cm2,与SrBi4TiO15(2Pr=12.2 μC/cm2)相比,提高117%.材料的矫顽场Ec在掺杂后增加仅为20%左右.SBTi的居里温度受掺杂的影响甚微,说明Mo对SrBi4Ti4O15的掺杂基本未影响材料原有的良好的热稳定性. 相似文献
8.
Y. S. Yu Haibo Li W. L. Li Mei Liu L. P. Yue W. D. Fei D. J. Sellmyer 《Applied Physics A: Materials Science & Processing》2011,103(2):301-307
FeAg and FeAg/Pt films were prepared by dc magnetron sputtering at room temperature. The effects of Ag volume fraction in
FeAg films and postannealing temperature and time on structure and magnetic properties of FeAg and FeAg/Pt films have been
investigated. The results show that the as-deposited FeAg films are metastable. After annealing at 300°C, the phase separation
of metastable FeAg films happened and the highest coercivity is obtained in Fe50Ag50/Pt film. With increasing annealing temperature, the ordering and the magnetic properties of the Fe50Ag50/Pt films were improved. When the Fe50Ag50/Pt films are annealed at 600°C for different annealing times, a long annealing time enhances the ordering of the metastable
Fe50Ag50/Pt films and affects the orientation development. When the films are annealed for a long time, the grain size and the magnetic
domain size also increase, which lead to an increase of correlation length due to the growth of FePt grains. 相似文献
9.
BaBi4Ti4O15 (BBT) ceramic was synthesized using mixed oxide route and the structural and electrical properties were investigated systematically. The structural studies confirmed it to be an n=4 member of the Aurivillius oxide. A broad dielectric peak with frequency dependent dielectric maximum temperature was observed. The dielectric relaxation obeyed the Vogel–Fulcher relation wherein f0=8.37E+14 Hz, Ea=0.13 eV, and Tf=608.18 K. The diffuseness parameter γ established the relaxor nature and it was attributed to the A-site cationic disorder. The specimen exhibited the excellent reproducibility in the measurements of displacement current, a remnant polarization of 5.4 μC/cm2, and a coercive field of 4.03 MV/m. The room temperature piezoelectric coefficient d33 was found to be 23 pC/N and the field-induced strain S was about 0.018% at the 8 MV/m electric field. 相似文献
10.
Dmitriev I. Yu. Kuryndin I. S. Lavrentyev V. K. Elyashevich G. K. 《Physics of the Solid State》2017,59(5):1041-1046
A method to produce microporous polyvinylidene fluoride films characterized by a high content of a piezoactive crystalline phase and a developed relief surface is elaborated. The porous films are obtained in the process based on melt extrusion with subsequent isometric annealing and uniaxial extension. It is found that the samples have an oriented lamellar structure containing both α- and β-modifications of the crystallites. The effect of temperature and degree of uniaxial extention of the annealed films on the characteristics of the porous samples, that is, the content of the piezoactive crystalline β-phase, overall porosity, breakdown voltage and the piezoelectric modulus is studied.
相似文献11.
按x=0 0 0 ,0 10 ,0 2 5 ,0 5 0 ,0 75和 1 0 0 ,采用固相烧结工艺 ,制备了不同La掺杂量的SrBi4-xLaxTi4O1 5的陶瓷样品 .用x射线衍射对其微结构进行了分析 ,并测量了铁电、介电性能 .结果发现 ,La掺杂未改变SrBi4Ti4O1 5的晶体结构 .随掺杂量的增加 ,样品的矫顽场 (Ec)下降 ,剩余极化 ( 2Pr)先增大 ,后减小 .在x =0 2 5时 ,2Pr 达到极大值 ,为2 4 2 μC·cm- 2 ,这时Ec=60 8kV·cm- 1 ,与SrBi4Ti4O1 5相比 ,2Pr 增加了近 5 0 % ,而Ec 下降了近 2 5 % ,材料铁电性能显著提高 .SrBi4-xLaxTi4O1 5的相变温度Tc 随x的增加逐渐降低 ,x =0 2 5时 ,Tc=45 1℃ .在x =0 75 ,1 0 0时 ,样品出现弛豫铁电体的典型特征 相似文献
12.
采用了传统的固相烧结工艺,制备了不同Zr和Hf掺杂量的SrBi4Ti4-xZrxO15(x=000,003, 006,010,020)和SrBi4Ti4-xHfxO15(x=000,0005, 0015,0030,0060)的陶瓷
关键词:
4Ti4-xZrxO15')" href="#">SrBi4Ti4-xZrxO15
4Ti4-xHfxO15')" href="#">SrBi4Ti4-xHfxO15
铁电性能
介电性能 相似文献
13.
Liang Zhao Jian‐Xiu Xu Na Yin Hong‐Chao Wang Cheng‐Ju Zhang Jin‐Feng Wang 《固体物理学:研究快报》2008,2(3):111-113
The cerium modified sodium bismuth titanate (Na0.5Bi4.5Ti4O15, NBT) piezoelectric ceramics have been prepared by using the conventional mixed oxide method. X‐ray diffraction analysis revealed that the cerium modified NBT ceramics have a pure four‐layer Aurivillius phase structure. The piezoelectric activity of NBT ceramics was found significantly improved by the modification of cerium. The Curie temperature Tc, and piezoelectric coefficient d33 for the NBT ceramics with 0.50 wt% cerium modification were found to be 655 °C, and 28 pC/N respectively. The Curie temperature gradually decreased from 668 °C to 653 °C with the increase of cerium modification. The dielectric spectroscopy showed that the samples possess stable piezoelectric properties, demonstrating practical potential that for high temperature applications. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
14.
Geetanjali Parida 《Phase Transitions》2013,86(5):452-459
In this study, Bi4Ti3O12–SrBi4Ti4O15 (BIT–SBTi) intergrowth ferroelectric ceramics was synthesized by a modified oxalate route. The phase formation behaviour, structure, morphology and electrical properties of the intergrowth ceramics were also investigated. The phase formation takes place through intermediate phases like SrBi2O4 and Bi12TiO20. The precursor mostly changes to Bi4Ti3O12 at 600°C and to BIT–SBTi intergrowth at 800°C. Rietveld analysis of the X-ray diffraction pattern showed that the structure of the intergrowth compound was orthorhombic with lattice parameters a = 5.4408(3), b = 5.4505(1) and c = 74.0851(4) Å. The intergrowth ferroelectrics showed a phase transition at 610°C and a frequency-stable permittivity and dielectric loss behaviour. The intergrowth ferroelectrics also showed a larger 2Pr than their constituents BIT and SBTi. 相似文献
15.
Lead free Ba0.92Ca0.08Ti0.95Zr0.05O3 (BCZT) thin films were deposited on Pt/Ti/SiO2/Si and LaNiO3(LNO)/Pt/Ti/SiO2/Si substrates by a sol–gel processing technique, respectively. The effects of substrate on structure, dielectric and piezoelectric properties were investigated in detail. The BCZT thin films deposited on LNO/Pt/Ti/SiO2/Si substrates exhibit (100) orientation, larger grain size and higher dielectric tunability (64%). The BCZT thin films deposited on Pt/Ti/SiO2/Si exhibit (110) orientation, higher Curie temperature (75 °C), better piezoelectric property (d33 of 50 pm/V) and lower dielectric loss (0.02). The differences in dielectric and piezoelectric properties in the two kinds of oriented BCZT films should be attributed to the difference of structure, in-plane stress and polarization rotation in orientation engineered BCZT films. 相似文献
16.
采用固相烧结工艺,制备了不同La掺杂量(x=0.00,0.25,0.50,0.75,1.00,1.25和1.50)的(Bi, La)4Ti3O12-Sr(Bi, La)4Ti4O15 (SrBi8-xLaxTi7O27)共生结构铁电陶瓷样品.用x射线衍射对其进行微结构分析,并测量铁电、介电性能.结果发现,La掺杂未改变Bi4Ti3O12-SrBi4Ti4O15共生结构铁电材料的晶体结构.随掺杂量的增加,样品的矫顽场(Ec)略有增加,剩余极化(2Pr)先增大,后减小.在x=0.50时,2Pr达到极大值,为25.6 μC*cm-2,与Bi4Ti3O12-SrBi4Ti4O15相比,2Pr增加了近60%,而Ec仅增加约10%.随La掺杂量的增加,样品的居里温度TC逐渐降低,x=0.50时,TC=556 ℃.在x=1.50时,样品出现弛豫铁电体的典型特征. 相似文献
17.
O. V. Gusakova V. G. Shepelevich 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(11):1504-1506
The effect of bismuth on the microstructure of ultrafast-quenched foils of Sn-Bi alloys has been investigated. Bismuth phase precipitation is observed in alloys containing more than 2 at % Bi. With an increase in the bismuth concentration to 8 at %, most precipitates acquire a needle-like shape. Cross-sectional inhomogeneity of the initial foils is revealed. It is found that addition of bismuth leads to an increase in the foil microhardness by a factor of 2.5. 相似文献
18.
The adsorption of O2 and CO on Ti films with thicknesses in the range 0–200 Å was investigated by quartz crystal microbalance (QCM) measurements. The O/Ti and CO/Ti ratios in the limit of zero film thickness was determined to be 1.5 and 0.5 respectively using the film thickness as a parameter. This result suggests that the oxide formed is Ti2O3. The Ti + O2 results are discussed in a model where the thinnest metal films are assumed to consist of metal islands. From the model an “oxidation depth” of ≈10 Å is estimated. 相似文献
19.
The piezoelectric properties of the cobalt‐modified sodium bismuth titanate (Na0.5Bi4.5Ti4O15, NBT) piezoelectric ceramics were investigated. The piezoelectric properties of NBT ceramics were significantly enhanced by cobalt modification. The Curie temperature TC and piezoelectric constant d33 for the 0.3 wt% cobalt‐modified NBT ceramics (NBT‐C3) were found to be 663 °C and 30 pC/N, respectively. Thermal annealing studies presented that the cobalt‐modified NBT ceramics possess stable piezoelectric properties, demonstrating that the cobalt‐modified NBT‐based ceramics are promising candidates for high temperature piezoelectric applications. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
20.
Both experimental and computer-simulated magneto-optical (MO) and optical spectroscopies of Co/Pt multilayered films (MLF) with a nearly constant Pt sublayer thickness and variable Co sublayer thickness, as well as pure Co and Pt, and Co0.51Pt0.49 alloy films, have been performed in the energy range 1.1–4.7 eV. The simulations were achieved by solving the multireflection task for various models of the MLF. The comparison between experimental and computer-simulated optical properties of the Co/Pt MLF allowed us to evaluate the thickness of the interfacial regions with the alloyed components. The diagonal and off-diagonal components of the optical conductivity tensor were calculated not only for the pure Co and Co0.51Pt0.49 alloy films, and the whole Co/Pt MLF, but also for the spin-polarized Pt layers in the Co/Pt MLF. 相似文献