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Volumn 66, Issue 6, 2002, Pages 641081-6410815

Phase transitions of Pb(ZrxTi1-x)O3 ceramics

Author keywords

[No Author keywords available]

Indexed keywords

LEAD; LEAD TITANATE ZIRCONATE; TITANIUM DIOXIDE; UNCLASSIFIED DRUG; ZIRCONIUM;

EID: 0036696949     PISSN: 01631829     EISSN: None     Source Type: Journal    
DOI: 10.1103/PhysRevB.66.064108     Document Type: Article
Times cited : (151)

References (45)
  • 20
    • 84988782783 scopus 로고    scopus 로고
    • note
    • In our previous article, Ref. 6, we erroneously talk about the Pmm2 space group in a case when the a and b axes were rotated by 45°, while the space group used was Cmm2.
  • 22
    • 84988782220 scopus 로고    scopus 로고
    • private communication
    • B. Noheda (private communication).
    • Noheda, B.1
  • 23
    • 84988761434 scopus 로고    scopus 로고
    • to be published August
    • In their recent work Noheda et al. [B. Noheda, L. Wu, and Y. Zhu, Phys. Rev. B (to be published August 2002)] assigned it to the space group Cc. However, NPD data provide no evidence for that symmetry. Particular care must be taken once electron diffraction patterns are interpreted: electron diffraction probes very small volumes of the samples and generally is not suited for an average symmetry determination, especially in a case of small distortions, such as those related to the oxygen octahedral tilts. Further, ion milling is very violent sample thinning technique, which easily generates significant defects. The particle size (in a nanometer scale) they report is not consistent with the superlattice reflections and overall sharp diffraction patterns observed by several groups (including Ref. 3). The explanation that local stresses, due to the cation disorder, generate Cc phase is questionable for the following reason: it is not a well-defined concept (which cations and which type of disorder?) and thus it is difficult to construct a model which would yield numerical values for the phase fractions as a function of temperature and average composition (recalling that this two-phase coexistence is limited to a rather narrow average composition interval, which the model should also explain). We feel that a more natural explanation is provided by the composition fluctuation, which allows one to estimate phase fractions in a quantitative manner.
    • (2002) Phys. Rev. b
    • Noheda, B.1    Wu, L.2    Zhu, Y.3
  • 27
    • 0036470879 scopus 로고    scopus 로고
    • 3 sample below 210 K. We note that this low-symmetry model predicts tens of reflections not experimentally observed, already in the low 2 θ range (only region for which fit, residuals, and Bragg reflection positions are shown, see their Fig. 2). This discrepancy becomes worse as high two-theta range (for which fit, residuals or Bragg reflection positions were not shown in Fig. 1) is considered. This in turn forced the authors to use extraordinary constraints during the refinement (which typically indicates that the symmetry used for the refinement is too low). More recently, an article by D. M. Hatch, H. T. Stokes, R. Ranjan, Ragini, S. K. Mishra, D. Pandey, and B. J. Kennedy, ibid. 65, 212101 (2002), assigning the Cc space group to the low-temperature symmetry of the x=0.52 sample, appeared. Inspection of Fig. 1 of this article reveals that the model predicts peaks not experimentally observed, which was the reason why we originally rejected this model in favor of the R3c symmetry. The reflections shown by arrows in their model are describable by the R3c symmetry. As a conclusion, we feel that there was no evidence for the Pc or Cc symmetries, and that there is no further need to speculate on their possible consequences. However, their low-temperature diffraction pattern, including the superlattice reflections, is consistent with the Cm+ R3c model.
    • (2002) Phys. Rev. B , vol.65 , pp. 060102
    • Ranjan, R.1    Ragini, S.K.2    Pandey, D.3    Kennedy, B.J.4
  • 33
    • 84988782117 scopus 로고    scopus 로고
    • note
    • We use the letter l instead of s used in the original definition in Ref. 29 to avoid confusion with the s parameter defined by Megaw and Darlington (Ref. 25).
  • 42
    • 84988786190 scopus 로고    scopus 로고
    • note
    • 3 is 0.0997. Note also that all thermal parameters tabulated in Table III in Ref. 6 must be divided by a factor of 100.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.