Synthesis and properties of AxV2Al20 (A = Th, U, Np, Pu) ternary actinide aluminides

JOURNAL OF ALLOYS AND COMPOUNDS

卷:696

Article

Winiarski, M. J.¹  Griveau, J. -C.²  Colineau, E.²  Wochowski, K.³  Wisniewski, P.³  Kaczorowski, D.³  Caciuffo, R.²  Klimczuk, T.¹ 

[1] Gdansk Univ Technol, Fac Appl Phys & Math, Narutowicza 11-12, PL-80233 Gdansk, Poland

[2] European Commiss, JRC, Directorate Nucl Safety & Secur, Postfach 2340, D-76125 Karlsruhe, Germany

[3] Polish Acad Sci, Inst Low Temp & Struct Res, POB 1410, PL-50950 Wroclaw, Poland

关键词: Actinide alloys and compounds;    Intermetallics;    Crystal structure;   

DOI  :  10.1016/j.jallcom.2016.12.033

来源: Elsevier

【 摘 要 】

Polycrystalline samples of A(x)V(2)Al(20) (A = Ce, Th, U, Np, Pu; 0.7 <= x <= 1.0) actinide intermetallics were synthesized using the arc-melting method. Crystal structure studies were performed by means of powder x-ray diffraction and the Rietveld refinement method. All studied compounds crystallize in the CeCr2Al20-type structure (space group Fd-3m, no. 227) with the actinide or Ce atom located in the oversized cage formed by Al atoms. Comparison of the crystallographic results with the reported data for LnV(2)Al(20) (Ln = lanthanides) counterparts reveals distinctly different behavior of the lanthanide-and actinide-bearing compounds. This difference is suggested to be caused by fairly localized character of the 4f electrons, whereas itinerant character of the 5f electrons is likely seen for U-and Np-containing phases. Magnetic susceptibility and specific heat measurements did not reveal any magnetic ordering in U0.8V2Al20, Np0.8V2Al20 and Pu0.8V2Al20 down to 2.5 K. A small anomaly in low-temperature specific heat of Ce0.8V2Al20, U0.8V2Al20, and Np0.8V2Al20 is observed, likely arising from a low-energy Einstein mode. (C) 2016 Elsevier B. V. All rights reserved.

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