Second order elastic constants of Pd, PdH/sub 0. 7/ and PdD/sub 0. 7/ between 1. 7 and 50 K

Conference · Tue Jan 01 00:00:00 EST 1985

OSTI ID:5693950

Pokert, D B; Schwarz, R B; Granato, A V

The second order elastic constants, c/sub 11/, c/sub 44/, and c' were measured in pure Pd, PdH/sub 0.7/ and PdD/sub 0.7/ as a function of temperature between 1.8 and 50 K. The data were fitted with polynomials c/sub ij/ (1 - a/sub ij/T/sup 2/ - b/sub ij/T/sup 4/). For Pd, a/sub ij/approx.10/sup -6/ and b/sub ij/approx.10/sup -10/. With the addition of H or D, c/sub 11/(0) decreases by 4%, c/sub 44/(0) decreases by 7%, and c'(0) increases by 8%. The most significant change occurs for the a/sub ij/, which decrease by a factor of 100. Furthermore, b/sub 11/ remains unchanged, while b/sub 44/ and b' decrease by factors of approximately 2-4. The changes in the c/sub ij/(0) cannot be explained simply in terms of the expansion of the Pd lattice with the addition of H or D. The decreases of the a/sub ij/ are attributed to a decrease in the first and second derivatives of the electronic density of states at the Fermi energy of Pd that occurs with the filling of the d-states by the electrons from H or D.

• Research Organization: Illinois Univ., Urbana (USA). Dept. of Physics; Los Alamos National Lab., NM (USA)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5693950
• Report Number(s): CONF-8506125-4; ON: DE85014316
• Resource Relation: Conference: Conference on internal friction and ultrasonic attenuation in solids, Urbana, IL, USA, 3 Jun 1985
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE
DEUTERIDES
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ELEMENTS
ENERGY LEVELS
HYDRIDES
HYDROGEN COMPOUNDS
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