Effect of CoO additive on structure and electrical properties of (Na0.5Bi0.5)0.93Ba0.07TiO3 ceramics prepared by the citrate method

Xu, Qing; Chen, Min; Chen, Wen; Liu, Hanxing; Kim, Bok‐Hee; Ahn, Byung-Kuk

doi:10.1016/j.actamat.2007.10.014

Cited by 125 publications

(52 citation statements)

References 25 publications

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“…Notably, two abnormal temperatures have been reported from electrical experiments for Co modified NBBTx%-based system, which were identified as phase transition temperature of ferroelectric to anti-ferroelectric (T FE−AFE ), and anti-ferroelectric to paraelectric (T AFE−PE ). 6,8,20 In this work, the two abnormal temperatures, from optical ellipsometry and Raman results, are comparable to consequences from electrical experiments. Therefore, the two abnormal temperatures of every x%-Co:NBBT6 crystals can be regarded as T FE−AFE and T AFE−PE , respectively.…”

Section: Resultssupporting

confidence: 67%

“…In fact, Co ions substituting for Ti 4+ will generate the oxygen vacancies in the lattice, which will shrink the unit cell. 6,8 Note that, it is the clamping effect of oxygen vacancies on domain walls that restrain ferroelectric to anti-ferroelectric and anti-ferroelectric to paraelectric phase transition with Co addition. Besides, the incorporation of smaller radius Co 3+ cations (0.525 Å) in the B-site sublattice of the ABO 3 perovskite is also helpful for the reduction in unit cell volume.…”

Section: Resultsmentioning

confidence: 99%

“…8,9 In most of the studies, Co cations are thought to exist only in Co 2+ or Co 3+ state. 6 that both Co 2+ and Co 3+ cations coexist in Co doped ceramics, and their relative concentrations are strongly associated with the addition. 8,9 Furthermore, optical spectra have been proven to be a powerful approach to investigate related issues on local configurations and phase transition.…”

Section: Introductionmentioning

confidence: 97%

“…[1][2][3][4][5] Among these, the Na 0.5 Bi 0.5 TiO 3 -x%BaTiO 3 (NBBTx%) binary system possess a rhombohedral-tetragonal morphotropic phase boundary in the region of 6<x<8, 1 where the system provides remarkably superior piezoelectric and dielectric properties than other NBT-based lead-free materials. 1,3 To meet the stringent requirements for specific applications, however, the electrical properties of the NBBTx% compositions need to be optimized, 6 which can be overcome through compositional modification by oxide doping. For example, cobalt oxide is believed to be an effective additive, based on the researches about Pb-, K 0.5 N 0.5 NbO 3 -and Na 0.5 Bi 0.5 TiO 3 -based ceramics, even adding a small amount of dopants.…”

Section: Introductionmentioning

confidence: 99%

“…For example, cobalt oxide is believed to be an effective additive, based on the researches about Pb-, K 0.5 N 0.5 NbO 3 -and Na 0.5 Bi 0.5 TiO 3 -based ceramics, even adding a small amount of dopants. [6][7][8][9][10][11] To further understand the doping mechanism of Co cations, it's significant to take the valence state of Co cations in the ceramics/crystals into account. 8,9 In most of the studies, Co cations are thought to exist only in Co 2+ or Co 3+ state.…”

Section: Introductionmentioning

confidence: 99%

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Electronic structures and abnormal phonon behaviors of cobalt-modified Na0.5Bi0.5TiO3-6%BaTiO3 single crystals

Huang

Zhang

et al. 2016

AIP Advances

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Optical properties, electronic structures, and structural variations of x wt% cobalt (Co) doped Na0.5Bi0.5TiO3-6%BaTiO3 (x=0%, 0.5%, 0.8%) single crystals have been studied by temperature-dependent optical ellipsometry and Raman spectra from 250 to 650 K. Based on the temperature evolution of electronic transitions (Ecp1 and Ecp2) and the phonon modes involving Ti-O vibrations, two critical temperature points exhibit an increasing trend with Co dopants, which are related to structural variations for ferroelectric to anti-ferroelectric, and anti-ferroelectric to paraelectric transition, respectively. Additionally, distinguishing abnormal phonon behaviors can be observed from Raman spectra for the crystal of x=0.5% and 0.8%, which show reverse frequency shift of the modes involving Ti-O vibration. It can be ascribed to different relative concentration of Co2+ and Co3+ in the crystals, which has been confirmed by X-ray Photoelectron Spectroscopy data.

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Section: Resultssupporting

confidence: 67%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Electronic structures and abnormal phonon behaviors of cobalt-modified Na0.5Bi0.5TiO3-6%BaTiO3 single crystals

Huang

Zhang

et al. 2016

AIP Advances

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Textured Bi_1/2Na_1/2TiO₃‐BaTiO₃ Lead‐Free Films with Enhanced Piezoelectric Property and Depolarization Temperature

Zhou

Zhang

et al. 2018

Adv Elect Materials

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largest usable strain shown in BNT-based solid solutions make them the most feasible lead-free materials for actuator applications. [1e,2] The major challenge for the technological application of BNT-based systems is the relatively low depolarization temperature (T d ), which is in the range from 80 to 100 °C for 0.94Bi 1/2 Na 1/2 TiO 3 -0.06BaTiO 3 (BNT-BT6). The thermal depolarization in BNT-based materials leads to a pronounced reduction of macroscopic electrical properties at T d , including the piezoelectric coefficient d 33 , the remanent polarization (P r ), and the negative strain (S neg ). [1d,3] As a consequence, the T d determines the maximum working temperature. Various approaches have been attempted to increase the T d . [4] Stress induced either by direct loading [4b] or by constructing composite structure [4a,d] is found to effectively increase the T d and broaden the temperature range in which the thermal depolarization takes place. It is believed that the stress, especially a uniaxial stress, can stabilize the ferroelectric long-range order and modulate the relaxor-toferroelectric (RE-FE) phase transition.In traditional ferroelectric thin films, the effect of stress on the phase transition temperature has been systematically studied. [5] Compared with bulk ceramics, it is much easier to introduce stress in thin films by modulating the properties of the sample and the substrate or the buffer layer, such as the thermal expansion coefficient and the lattice parameter. An efficient enhancement in Curie temperature (T c ) has been found by inducing the in-plane stress in several ferroelectric materials, such as PbTiO 3 and BaTiO 3 . [5,6] The enhancement of T c in ferroelectric perovskites has been explained by Devonshire thermodynamic formalism and interpreted as a stabilization of the long-range ferroelectric order. [6a,7] Through strain engineering, the in-plane stress could not only increase the T c but also enhance the ferroelectric properties of BaTiO 3 thin films. [8] It is worth mentioning that the stress-induced stabilization of the long-range ferroelectric order is only applicable to the case when the stress is perpendicular to or along the polarization vectors. Consequently, to enhance the phase transition temperature by modulating the in-plane stress, the film with specific orientations is preferred.Based on the analysis above, it is expected that the stabilization of long-range ferroelectric orders through Future microelectromechanical systems will need environmentally friendly lead-free piezoelectrics in the form of thin films, like Bi 1/2 Na 1/2 TiO 3 (BNT); however, its application is limited due to the relatively low depolarization temperature (T d ). In this work, not only enhanced piezoelectric properties, but also higher T d , are achieved in (001)-textured 0.94Bi 1/2 Na 1/2 TiO 3 -0.06BaTiO 3 (BNT-BT6) thin films on widely used platinized Si wafers with a LaNiO 3 buffer layer. The piezoelectric coefficient a 33,eff is increased by 65% to 43 pm V −1 in the textured films fr...

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High dielectric permittivity and percolative behavior of polyvinyl alcohol/potassium dihydrogen phosphate composites

Uddin

Sannigrahi

Masud

et al. 2012

J of Applied Polymer Sci

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A new kind of anhydrous, transparent, and flexible potassium dihydrogen phosphate (KH2PO4 or KDP)/polyvinyl alcohol (PVA) composite in the form of film (0.10 mm) has been prepared by solution casting technique. KDP is well dispersed in the polymer matrix as observed from the microstructural studies. Frequency and temperature dependent dielectric properties of the composites have been studied with varying KDP concentrations. The PVA/KDP composite films exhibited extraordinarily high relative permittivity ε′ ∼ 430 (80 times higher compared with pure PVA and even higher than KDP) near the percolation threshold (ϕC = 2.5 wt % KDP) with low dielectric losses (∼ 0.15) at 1 kHz and room temperature. Such flexible, low loss and high dielectric permittivity material has enormous importance for application in devices. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

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Effect of CoO additive on structure and electrical properties of (Na0.5Bi0.5)0.93Ba0.07TiO3 ceramics prepared by the citrate method

Cited by 125 publications

References 25 publications

Electronic structures and abnormal phonon behaviors of cobalt-modified Na0.5Bi0.5TiO3-6%BaTiO3 single crystals

Electronic structures and abnormal phonon behaviors of cobalt-modified Na0.5Bi0.5TiO3-6%BaTiO3 single crystals

Textured Bi_1/2Na_1/2TiO₃‐BaTiO₃ Lead‐Free Films with Enhanced Piezoelectric Property and Depolarization Temperature

High dielectric permittivity and percolative behavior of polyvinyl alcohol/potassium dihydrogen phosphate composites

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Effect of CoO additive on structure and electrical properties of (Na0.5Bi0.5)0.93Ba0.07TiO3 ceramics prepared by the citrate method

Cited by 125 publications

References 25 publications

Electronic structures and abnormal phonon behaviors of cobalt-modified Na0.5Bi0.5TiO3-6%BaTiO3 single crystals

Electronic structures and abnormal phonon behaviors of cobalt-modified Na0.5Bi0.5TiO3-6%BaTiO3 single crystals

Textured Bi1/2Na1/2TiO3‐BaTiO3 Lead‐Free Films with Enhanced Piezoelectric Property and Depolarization Temperature

High dielectric permittivity and percolative behavior of polyvinyl alcohol/potassium dihydrogen phosphate composites

Contact Info

Product

Resources

About

Textured Bi_1/2Na_1/2TiO₃‐BaTiO₃ Lead‐Free Films with Enhanced Piezoelectric Property and Depolarization Temperature