Unusual Behaviour of (Np,Pu)B2C

Two transuranium metal boron carbides, NpB2C and PuB2C have been synthesized by argon arc melting. The crystal structures of the {Np,Pu}B2C compounds were determined from single-crystal X-ray data to be isotypic with the ThB2C-type (space group R3m, a = 0.6532(2) nm; c = 1.0769(3) nm for 15 NpB2C and a = 0.6509(2) nm; c = 1.0818(3) nm for PuB2C; Z = 9). Physical properties have been derived from polycrystalline bulk material in the temperature range from 2 to 300 K and in magnetic fields up to 9 T. Magnetic susceptibility and heat capacity data indicate the occurrence of antiferromagnetic ordering for NpB2C with a Neel temperature TN = 68 K. PuB2C is a Pauli 20 paramagnet most likely due to a strong hybridization of s(p,d) electrons with the Pu-5f states. A pseudo-gap, as concluded from the Sommerfeld value and the electronic transport, is thought to be a consequence of the hybridization. The magnetic behaviour of {Np,Pu}B2C is consistent with the criterion of Hill.

KLIMCZUK Tomasz;  BOULET Pascal;  GRIVEAU Jean-Christophe;  COLINEAU Eric;  BAUER E.;  FALMBIGL Matthias;  ROGL P.;  WASTIN Franck; 

2016-01-04

TAYLOR & FRANCIS LTD

JRC89613

1478-6435,   

http://www.tandfonline.com/doi/abs/10.1080/14786435.2015.1009520,    https://publications.jrc.ec.europa.eu/repository/handle/JRC89613,   

10.1080/14786435.2015.1009520,