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Abstract |
Magnetic (chi), thermal(C-p), and transport (p) measurements on Ce(l4)X(51) (X = Au, Ag and Cu) are presented. All these compounds show antiferromagnetic type order at low temperatures, with T-N = 0.9 K (Au), 1.1 K (Ag) and 3.2 K (Cu). Within the Gd14Ag51-type structure the Ce atoms sit in different sublattices denoted by I (2 atoms), II (6 atoms) and III (6 atoms), therefore the results can be interpreted in terms of three different behaviors of Ce depending on its local environment. From the entropy involved in the magnetically ordered (MO) phase it can be established that the Ce-II and Ce-III atoms order in Cel4Au51 and Ce14Ag51, while the Ce-I order in Cel4Cu51. There is a large linear contribution to Cp at T > T-N,T-gamma HT = 0.81 (Au), 1.24 (Ag) and 3.1 (Cu) J/mol K-2, which indicates the coexistence of MO and heavy fermions. In the case of Cel4Cu51, the magnetic contribution to Cp from sublattice Ce-I around T-N,T- resembles that of a modulated system and the characteristic temperatures for Ce-II and Ce-III atoms are estimated from p(T) as:T-K=16 K and >120 K respectively. |
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