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Pb(B{prime}{sub 1/2}B{double_prime}{sub 1/2})O{sub 3}-Type perovskites: Part I. Pair-correlation theory of order-disorder phase transition

Journal Article · · Journal of Materials Research
;  [1]
  1. Department of Materials Science and Engineering
The limitation of the long-range order parameter and the necessity of the short-range order parameter for the thermodynamic description of Pb(B{sup {prime}}{sub 1/2}B{sup {prime}{prime}}{sub 1/2})O{sub 3}-type perovskites were discussed. Based on the discussion, a statistical thermodynamic model that takes into account the configuration of the neighboring B-site ions (B{sup {prime}} and B{sup {prime}{prime}} cations) was developed. A pair-correlation approximation was used in the calculation of the configurational entropy and the long-range coulombic interaction energy between the nearest B-site ions. The theoretical calculations using Pb(Sc{sub 1/2}Ta{sub 1/2})O{sub 3} (PST) and Pb(Sc{sub 1/2}Nb{sub 1/2})O{sub 3} (PSN) systems indicate that the short-range order parameter persists over a wide range of temperature examined (0{approximately}1800K) and that there possibly occur consecutive long-range order-disorder transitions in the configuration of B-site cations. The possibility of the existence of short-range ordering above the long-range order-disorder transition temperature was also examined using the annealed PSN specimen as a typical example of Pb(B{sup {prime}}{sub 1/2}B{sup {prime}{prime}}{sub 1/2})O{sub 3}-type perovskites. {copyright} {ital 1997 Materials Research Society.}
OSTI ID:
542190
Journal Information:
Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 8 Vol. 12; ISSN JMREEE; ISSN 0884-2914
Country of Publication:
United States
Language:
English