High‐pressure Synthesis of Perovskite‐Type Pb(Zn1/3Nb2/3)O3

Matsuo, Yuichi; Sasaki, Hiromu; Hayakawa, Shigeru; Kanamaru, Fumikazu; Koizumi, M.

doi:10.1111/j.1151-2916.1969.tb09210.x

Cited by 88 publications

(17 citation statements)

References 5 publications

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“…Pb(Zn 1/3 Nb 2/3 )O 3 and Pb(Zn 1/3 -Ta 2/3 )O 3 (PZN and PZTa, respectively) are well-known pyrochlore-prone compositions, perovskite formation of which by conventional solid-state reaction has not succeeded yet. Instead, perovskite powder of the former could only be prepared by applying high pressure [21] or mechanochemical milling [22], whereas synthesis of the latter by any means is still unreported. Between the two compositions, perovskite formation in PZN was achieved at substantially lower concentrations, regardless of PT and BT.…”

Section: Resultsmentioning

confidence: 98%

Phase formation and dielectric properties of (Pb,Ba)[(Zn1/2W1/2),Ti]O3 ceramics

Cho¹,

Lee²,

Kim³

2009

Ceramics International

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Section: Resultsmentioning

confidence: 98%

Phase formation and dielectric properties of (Pb,Ba)[(Zn1/2W1/2),Ti]O3 ceramics

Cho¹,

Lee²,

Kim³

2009

Ceramics International

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“…For instance, PZN can be synthesized under high pressure (from 1.5 to 3.5 GPa) and high temperature (about 1100 C to 1200 C). 33,34 Under high pressure, the coordination number of Zn 2þ with O 2À in ZnO transforms from the wurtzite-type structure (4-coordination) to rocksalttype structure (6-coordination), 35 and the coordination number of Pb 2þ with O 2À in PbO transforms from the CsCl-type structure (8-coordination) to the NaCl-type structure (6-coordination). 36 These geometric transforms at higher pressure are then suitable for perovskite structural formation, where the high enough temperature can also compensate the mutual interaction between Pb 2þ lone pair and Zn 2þ cation.…”

Section: Resultsmentioning

confidence: 99%

Probing local structure of pyrochlore lead zinc niobate with synchrotron x-ray absorption spectroscopy technique

Kanchiang

Pramchu

Yimnirun

et al. 2013

Journal of Applied Physics

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Local structure of lead zinc niobate (PZN) ceramic, synthesized via B-site oxide precursor route in atmospheric pressure, was investigated using synchrotron x-ray absorption spectroscopy (XAS) technique. The x-ray absorption near-edge structure (XANES) simulation was first carried out. The XANES simulation results indicate that the PZN ceramic is in pyrochlore phase having Zn 2þ substituted on Nb 5þ site. Afterwards, the extended x-ray absorption fine structure (EXAFS) analysis was performed to extract the bond length information between Zn 2þ and its neighboring atoms. From the EXAFS fitting, the bond length between Zn 2þ and Pb 2þ in the pyrochlore phase was found to be longer than the previously reported bond length in the perovskite phase. Further, with the radial distribution information of Zn 2þ 's neighboring atoms, the formation energies along the precursor-to-pyrochlore and precursor-to-perovskite reaction paths were calculated using the density functional theory (DFT). The calculated results show that the formation energy of the perovskite phase is noticeably higher than that of the pyrochlore phase, which is influenced by the presence of energetic Pb 2þ lone pair, as the perovskite phase has shorter Zn 2þ to Pb 2þ bonding. This therefore suggests the steric hindrance of Pb 2þ lone pair and the mutual interactions between Pb 2þ lone pair and Zn 2þ are main causes of the instability of lead zinc niobate in the perovskite structure and confirm the efficacy of XAS and DFT analysis in revealing local structural details of complex pyrochlore materials. V C 2013 AIP Publishing LLC. [http://dx.

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“…The only published work where pure‐phase PZN polycrystals have been synthesized was under a pressure of >20 kbar at temperatures between 750° and 950°C 11 . Beyond this temperature range, the most common second phase found in that study was Pb 2 Nb 2 O 7 , with minor amounts of PbO and ZnO.…”

Section: Introductionmentioning

confidence: 89%

High‐Temperature Stability of Lead Zinc Niobate: In Situ X‐Ray Diffraction

Shanahan

Kisi

Forrester

et al. 2010

Journal of the American Ceramic Society

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The thermal stability of the relaxor ferroelectric Pb(Zn1/3Nb2/3)O3 (PZN) upon heating was studied using high‐temperature X‐ray diffraction (XRD) and scanning electron microscopy. It was found that single‐phase PZN is stable below 700°C, whereupon the first decomposition phase, the pyrochlore Pb1.83 Nb1.71Zn0.29O6.39 was observed. With the increasing temperature, the amount of pyrochlore increased until at 1100°C there is no PZN remaining. Pyrochlore formation was accompanied by the precipitation of ZnO above 800°C and after holding at 1100°C, the formation of Nb2ZnO6. Rietveld refinements based on the XRD patterns have allowed the relative phase proportions as well as the atomic site occupancies of the metal ions in PZN and the pyrochlore to be estimated. The Zn site occupancy within the perovskite PZN decreases upon heating in parallel with the pyrochlore formation. An elemental mass balance based on the XRD results shows that PZN decomposition is well under way before any Pb is lost from the sample. This indicates that Zn egress rather than Pb volatility is the determining factor in the instability of PZN, contrary to prior published work.

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High‐pressure Synthesis of Perovskite‐Type Pb(Zn_1/3Nb_2/3)O₃

Cited by 88 publications

References 5 publications

Phase formation and dielectric properties of (Pb,Ba)[(Zn1/2W1/2),Ti]O3 ceramics

Phase formation and dielectric properties of (Pb,Ba)[(Zn1/2W1/2),Ti]O3 ceramics

Probing local structure of pyrochlore lead zinc niobate with synchrotron x-ray absorption spectroscopy technique

High‐Temperature Stability of Lead Zinc Niobate: In Situ X‐Ray Diffraction

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