Polycrystalline samples of AxV2Al20 (A ¼ 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 LnV2Al20 (Ln ¼ 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.

WINIARSKI M. J.;  GRIVEAU Jean-Christophe;  COLINEAU Eric;  WOCHOWSKI K;  WISNIEWSKI P;  KACZOROWSKI D.;  CACIUFFO Roberto;  KLIMCZUK Tomasz; 

2017-01-13

ELSEVIER SCIENCE SA

JRC102461

0925-8388,   

http://www.sciencedirect.com/science/article/pii/S092583881633941X,    http://dx.doi.org/10.1016/j.jallcom.2016.12.033,    https://publications.jrc.ec.europa.eu/repository/handle/JRC102461,   

10.1016/j.jallcom.2016.12.033,