Electronic and atomic structure of Mn-doped CaF sub 2 : An x-ray-absorption near-edge structure and extended x-ray-absorption fine-structure study

Journal Article · Thu Oct 01 00:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.46.8768· OSTI ID:7038404

Barkyoumb, J H; Mansour, A N ^[1]

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1. Naval Surface Warfare Center, Research and Technology Department, Silver Spring, Maryland 20903 (United States)

X-ray-absorption near-edge structure (XANES) and extended-x-ray-absorption fine-structure (EXAFS) measurements have been performed on the calcium {ital K} edge and manganese {ital K} edge of CaF{sub 2} doped with manganese at molecular concentrations of 0.1--2.5 %. The results are compared to other measurements of the calcium {ital K} edge in CaF{sub 2} and the Mn {ital K} edge in various manganese compounds. Major features in the XANES spectra are tentatively identified with transitions to high-symmetry points of the CaF{sub 2} energy bands in a one-electron picture. Expected deviations from the structure predicted by the one-electron formalism are discussed. The EXAFS analysis shows a reduction in the manganese-fluorine distance of (3.9{plus minus}0.4)% as compared to the calcium-fluorine separation in the doped or undoped samples. This compares well with previous results obtained by EPR. A significant increase in disorder of the first shell around the Mn dopant ion is observed as compared to the Ca ion. The significance of this shell contraction and disorder is discussed in terms of possible defect structures in the material.

• DOE Contract Number: AS05-80ER10742; AC02-76CH00016
• OSTI ID: 7038404
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 46:14; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALCIUM FLUORIDES
ELECTRONIC STRUCTURE
ABSORPTION SPECTRA
MANGANESE ADDITIONS
X RADIATION
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
CALCIUM COMPOUNDS
CALCIUM HALIDES
ELECTROMAGNETIC RADIATION
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
IONIZING RADIATIONS
MANGANESE ALLOYS
RADIATIONS
SPECTRA
360602* - Other Materials- Structure & Phase Studies
360606 - Other Materials- Physical Properties- (1992-)