Large atomic disorder in nanostructured LaNi5 alloys: A La L3-edge extended X-ray absorption fine structure study |
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Authors: | B. Joseph A. Iadecola A. Cognigni N.L. Saini |
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Affiliation: | a Dipartimento di Fisica, Università di Roma “La Sapienza”, P. le Aldo Moro 2, 00185 Roma, Italy b Istituto Tecnologie Avanzate, Base di ASI Luigi Broglio, Strada Statale 113, Trapani 9100, Italy c Dipartimento di Fisica e Tecnologie Relative, Università di Palermo, Viale delle Sicenze, Palermo 90100, Italy d Elettra Sincrotrone Trieste S.C.p.A., Area Science Park, SS 14, Km 163.5, I-34012 Trieste, Italy |
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Abstract: | Local structure of the nanostructured LaNi5 alloys, prepared by ball-milling, has been studied using La L3-edge extended X-ray absorption fine structure spectroscopy. The near-neighbor distances tend to decrease with the ball-milling, and the mean square relative displacements (MSRD) show substantial increase suggesting an increased atomic disorder. High temperature annealing helps in partial recovery of atomic order in the ball-milled samples for milling times upto 20 h, however, the long-time ball-milled samples seems to gain only a local random order. The results suggest that reduced unit-cell volume together with large atomic-disorder might be causing a higher energy-barrier for the hydride-phase formation in the long time ball-milled LaNi5 powders. |
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Keywords: | A. LaNi5 alloys A. Nanostructuring C. EXAFS D. Crystal structure |
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