FTs of from Pu L 3-edge data for (a) PuAl2 and (b) PuCoIn5. Transforms are from 2.5 to 14.0 Å−1, Gaussian narrowed by 0.3 Å−1.
FT magnitudes for Pu2PtGa8 from (a) Pu L 3-edge and (b) Ga K-edge data. Transforms are from 2.5 to 14.0 Å−1 for the Pu L 3-edge data, and from 2.5 to 13.9 Å−1 for the Ga K-edge data, each Gaussian narrowed by 0.3 Å−1.
Self-irradiation-induced damage fractions (Fd ) measured from the Pu L 3 edge for samples stored at room temperature ( ), unless otherwise noted. Connecting lines for the PuGa3 and PuAl2 data are only guides to the eye. The solid gray line shows model “m1,” Eq. (1) with 90 000 distortions per decay and the annealing rate constant K = 0. Note that the data are from a sample with 4.3 at. % Ga, while the data are from a 1.9 at. % Ga sample. The 4.3 at. % Ga sample also has some intrinsic disorder; see text for more information.
FTs of data and fit results for 30 K data on δ-Pu: 1.9 at. % Ga, from both (a) the Pu L 3 edge and (b) the Ga K edge. The first peak at ∼3.1 Å contains the signal from the 12 nearest neighbor Pu-Pu pairs in the fcc structure at 3.25 Å, as well as the 1.9% Ga contributions. Transform ranges are as given in Fig. 2 .
EXAFS magnitudes at low temperature for δ-Pu samples with Ga concentrations of 1.9 at. % (30 K), 4.3 at. % (5 K), and 7.0 at. % (30 K) from the (a) Pu L 3 edge and (b) the Ga K edge. Transforms are from 2.5 to 14.0 Å–1 for the Pu L 3-edge data, and from 2.5 to 13.9 Å−1 for the Ga K-edge data, each Gaussian narrowed by 0.3 Å−1. All samples had been at RT directly before measurement.
EXAFS magnitudes for the δ-Pu: 4.3 at. % Ga sample at low temperature from (a) the Pu L 3 edge and (b) the Ga K edge for sample ages since last anneal of 0.0 α-decays per atom at 30 K, 3.2 × 10−6 α-decays per atom at 5.5 K, and 6.5 × 10−6 α-decays per atom at 5.0 K.
Local structure damage results for cold-stored δ-Pu sample. (a)Total damage fraction as measured by EXAFS as a function of temperature on warming after stored for 2 months below 32 K. (b) Same data as in (a) replotted as the change in measured damage from T = 5 K, normalized by the measured damage at 5 K. Note that unphysical results can occur if the EXAFS amplitude actually increases with time. The estimated errors indicate such results are consistent with no developed damage. The EXAFS data are also compared to previous resistivity 35 and susceptibility 14 data, similarly normalized taking and , respectively.
Total damage fraction Fd calculated from the simple equilibrium models described in the text. Each model uses the same damage production rate of 90 000 distorted atoms per decay. Model “m1” has no annealing, and the annealing rate increases from “m2” through “m4.” Data shown follow legend from Fig. 3 , with δ-Pu for (stars), PuCoGa5 (filled squares), PuAl2 (triangles), and δ-Pu for (inverted triangles).
Fit results from δ-Pu:1.9 at. % Ga data collected at 30 K. Fit range is between 2.5 and 6.6 Å, including all single-scattering paths as reported, as well as multiple scatter paths. The k 3-weighted Pu L 3-edge data are transformed between 2.5 and 14.0 Å−1, and the Ga K-edge data are transformed between 2.5 and 13.9 Å−1, each Gaussian narrowed by 0.3 Å−1. The correlated-Debye fit results are from data collected at 30, 100, 200, and 300 K, and are only obtained from the s of the nearest-neighbor at 3.27 Å. Reported errors are determined using a Monte Carlo method 24 and primarily reflect reproducibility. Absolute errors for are about 10% for near neighbors and 20% for further neighbors, and for R are about 0.005 Å for near neighbors and 0.02 Å for further neighbors. 19
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