Studies of vibrational properties in Ga stabilized delta-Pu by extended X-ray absorption fine structure

Journal Article · Thu Feb 14 04:00:00 EST 2002 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.65.214107· OSTI ID:797841

Allen, P G ^[1]; Henderson, A L; Sylwester, E R; Turchi, P E.A.; Shen, T H; Gallegos, G F; Booth, C H

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1. LBNL Library

Temperature dependent extended x-ray absorption fine structure (EXAFS) spectra were measured for a 3.3 at. % Ga stabilized Pu alloy over the range T= 20 - 300 K. EXAFS data were acquired at both the Ga K-edge and the Pu L{sub III} edge. Curve-fits were performed to the first shell interactions to obtain pair-distance distribution widths, {sigma}, as a function of temperature. The temperature dependence of {sigma}(T) was accurately modeled using a correlated-Debye model for the lattice vibrational properties, suggesting Debye-like behavior in this material. Using this formalism, we obtain pair-specific correlated-Debye temperatures, {Theta}{sub cD}, of 110.7 {+-} 1.7 K and 202.6 {+-} 3.7 K, for the Pu-Pu and Ga-Pu pairs, respectively. The result for the Pu-{Theta}{sub cD} value compares well with previous vibrational studies on {delta}-Pu. In addition, our results represent the first unambiguous determination of Ga-specific vibrational properties in Pu-Ga alloys, i.e, {Theta}{sub cD} for the Ga-Pu pair. Because the Debye temperature can be related to a measure of the lattice stiffness, these results indicate the Ga-Pu bonds are significantly stronger than the Pu-Pu bonds. This effect has important implications for lattice stabilization mechanisms in these alloys.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director, Office of Science. Office of Basic Energy Studies. Chemical Sciences, Geosciences, and Biosciences Division (US)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 797841
• Report Number(s): LBNL--49403; UCRL-JC-146442 (LLNL); B& R KC0302030
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 21 Vol. 65
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
ALLOYS
DEBYE TEMPERATURE
DISTRIBUTION
FINE STRUCTURE
STABILIZATION
TEMPERATURE DEPENDENCE
XAFS ACTINIDES LATTICE DISORDER