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Article
Structural Characterization of a High-Temperature, Ionic Conducting Ceramic using Perturbed Angular Correlation Spectroscopy
Physical Review B
  • Gary L. Catchen
  • Michael Blaszkiewicz
  • Khalid Jamil
  • Dinesh K. Agrawal
  • Wayne Huebner, Missouri University of Science and Technology
  • Herbert A. McKinstry
  • Lorenz H. Menke, Jr.
Abstract
Perturbed angular correlation (PAC) spectroscopy has been used to characterize several structural aspects of a high-temperature, ionic conducting ceramic, CaZr3.95Hf0.05P6O24. Hafnium was introduced into the material to provide the PAC probe nuclei, 181Hf/181Ta, which were located primarily at Zr sites. PAC measurements were made over a range of temperatures from 77 to 1180 K, and they have been analyzed and interpreted using several simple models. The distorted octahedral crystal field at the Zr site produced a (low-frequency) static electric quadrupole interaction which can be accurately described by the point-charge model. But, the temperature dependence of the associated electric field gradient (EFG) cannot be described accurately by purely static considerations via the point-charge model and high-temperature x-ray diffraction data. Although a high-frequency static interaction was also observed, the measurements were not sufficiently accurate to identify its origin unambiguously. Some of the high-temperature measurements show evidence of a time-varying interaction, which may result from Ca2+-ion jumping. But, jump frequencies derived classically from high-temperature electrical dc conductivity measurements are too low to agree with those indicated by the PAC data. However, the dc conductivity measurements support a simple model of thermally activated Ca2+-ion transport. The temperature dependence of the EFG (corresponding to the low-frequency interaction) was used to determine an effective Debye-Waller factor. As a result of using this approach to analyze this type of PAC data, this factor was shown also to agree qualitatively with the predictions of the Debye crystal model, although significant theoretical limitations were encountered. These particular results suggest that the PAC technique may provide new insights into understanding advanced ceramic materials.
Department(s)
Materials Science and Engineering
Sponsor(s)
Pennsylvania State University College of Engineering
Pennsylvania State University. Department of Nuclear Engineering
FERMI Industrial Consortium
Keywords and Phrases
  • Debye Crystal Model,
  • Electric Field Gradient (EFG),
  • Octahedral Crystal Field,
  • Perturbed Angular Correlation (PAC),
  • Point-Charge Model,
  • Spectroscopy,
  • Static Electric Quadrupole
Library of Congress Subject Headings
Hafnium
Document Type
Article - Journal
Document Version
Final Version
File Type
text
Language(s)
English
Rights
© 1988 American Physical Society (APS), All rights reserved.
Publication Date
4-1-1988
Citation Information
Gary L. Catchen, Michael Blaszkiewicz, Khalid Jamil, Dinesh K. Agrawal, et al.. "Structural Characterization of a High-Temperature, Ionic Conducting Ceramic using Perturbed Angular Correlation Spectroscopy" Physical Review B (1988)
Available at: http://works.bepress.com/wayne-huebner/50/