Dielectric Properties of Ceramics in Ba (Co1/3 Nb2/3)O3–Ba(Zn1/3Nb2/3)O3 Solid Solution

Endo, Kazuaki; Fujimoto, Kenji; Murakawa, K.

doi:10.1111/j.1151-2916.1987.tb05746.x

Cited by 99 publications

(18 citation statements)

References 6 publications

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“…However, for Ba(B' 1/3 Nb 2/3 )O 3 complex perovskite, the unacceptably higher τ f needs to be tuned to near-zero for practical applications. 14,15 Moreover, most of the Nb-based complex perovskite systems are susceptible to order-disorder transition or forming secondary phases during sintering, thus complicate the processing procedures. [16][17][18] In the previous investigations, improved microwave properties have been gained for Ba[(Mg 1-x Ni x ) 1/3 Nb 2/3 ]O 3 ceramics through processing optimization and post-densification annealing.…”

Section: Introductionmentioning

confidence: 99%

Raman spectra analysis for Ba[(Mg1- x Ni x )1/3Nb2/3]O3 microwave dielectric ceramics

Sun

Chen

2015

AIP Advances

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Raman spectra analysis has been carried out for both the as-sintered and annealed Ba[(Mg1−xNix)1/3Nb2/3]O3 ceramics. Based on the harmonic resonant model, all the Raman modes are successfully assigned according to the effects of ion substitution and post-densification annealing. All of the as-sintered samples present 7 normal modes as predicted by factor group analysis; an extra mode at around 560 cm−1 exists in x = 0.6-1.0. The 3 modes Eg(O), Eg(Nb), A1g(Nb) between 150-350 cm−1 decrease in intensity with increasing x, agreeing well with the variation of ordering degree. By post-densification annealing for x = 0.4, a strong dependence on ordering degree has been proved for the A1g(O) mode at around 790 cm−1. For the as-sintered samples, the Q × f value correlates well with the oxygen octahedron stretch mode A1g(O), while the dielectric constant εr is dominated by ionic polarizability rather than the rigidity of the oxygen octahedra. After annealing, the Raman modes are intensified, corresponding to the enhancement of cations ordering. The annealing significantly increases the A1g(O) Raman shift and decreases the FWHM (full width at half maximum) of A1g(O) mode, resulting in the increase of εr and the improvement of Q × f value for each composition. The intensity ratio of A1g(Ba)+Eg(Ba) mode to A1g(O) mode increases after annealing, implying that A1g(Ba)+Eg(Ba) is more dominant in the ordered structure.

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Section: Introductionmentioning

confidence: 99%

Raman spectra analysis for Ba[(Mg1- x Ni x )1/3Nb2/3]O3 microwave dielectric ceramics

Sun

Chen

2015

AIP Advances

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“…factor (Q × f = 56,000-85,000 GHz) and small temperature coefficient of resonant frequency (τ f ∼0). 4,6,7 However, to obtain dense ceramics at temperatures below 1450 • C, a sintering aid is required.…”

Section: Introductionmentioning

confidence: 99%

Effect of CeO2 on the sintering behaviour, cation order and properties of Ba3Co0.7Zn0.3Nb2O9 ceramics

Azough

Leach

Freer

2006

Journal of the European Ceramic Society

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The effect of low-level CeO 2 addition and cooling rate on sintering, microstructures, phase formation, 1:2 ordering and microwave dielectric properties of Ba 3 Co 0.7 Zn 0.3 Nb 9 (BCZN) was investigated. It was found that low levels doping of CeO 2 (up to 0.5 wt.%) could significantly improve densification of the specimens and their properties. Dielectric properties of CeO 2 -doped samples were sensitive to 1:2 ordering in the B-site. Slow cooling after sintering improved the unloaded quality factor (Q × f values) significantly. The B-site ordering parameter (S) and lattice constant (c/a) values increased as the cooling rate decreased. Ba 5 Nb 4 O 15 (5/0/4) and Ba 8 (Co,Zn) 1 Nb 6 O 24 (8/1/6) secondary phases were found on the surface of all the samples. At 0.4 wt.% CeO 2 the specimens showed maximum Q × f of 84,000 GHz attributed to high density and the degree of cation ordering.

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“…For example, BCN has a relative permittivity of 32, a quality factor (Q × f) greater than 50,000 GHz and negative temperature coefficient of resonant frequency (τ f ) which can adjusted to zero by Zn substitution. [5][6][7][8] BCN crystallizes in either a disordered cubic structure or in an ordered hexagonal structure. The ordered structure results from the 1:2 ordering of B and B cations along the 1 1 1 directions of the cubic unit cell.…”

Section: Introductionmentioning

confidence: 99%

Effect of nonstoichiometry on the structure and microwave dielectric properties of Ba(Co1/3Nb2/3)O3 ceramics

Azough

Leach

Freer

2006

Journal of the European Ceramic Society

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Dielectric Properties of Ceramics in Ba (Co_1/3 Nb_2/3)O₃–Ba(Zn_1/3Nb_2/3)O₃ Solid Solution

Cited by 99 publications

References 6 publications

Raman spectra analysis for Ba[(Mg1- x Ni x )1/3Nb2/3]O3 microwave dielectric ceramics

Raman spectra analysis for Ba[(Mg1- x Ni x )1/3Nb2/3]O3 microwave dielectric ceramics

Effect of CeO2 on the sintering behaviour, cation order and properties of Ba3Co0.7Zn0.3Nb2O9 ceramics

Effect of nonstoichiometry on the structure and microwave dielectric properties of Ba(Co1/3Nb2/3)O3 ceramics

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