Ceftiofur Standard (98%)

We report the crystal structure as well as the magnetic, electronic and transport properties of PrCu2Au3 which crystallizes in the MgCu4Sn-type structure with the cubic space group F (4) over bar 3m (No. 216). In this structure, the Pr3+ ion sits on a lattice site with the cubic T-d symmetry which dictates the crystal electric field (CEF) splitting of the Hund's H-3(4) ground multiplet into four levels. The sample has been investigated by measurements of temperature dependences of specific heat, C-p(T), electrical resistivity, p(T), magnetic susceptibility, chi(T), isothermal magnetization, M(B, T), thermal conductivity, k(T) (T) and thermoelectric power, S(T). chi(T) follows a Curie-Weiss behavior above 100 K with an effective magnetic moment, mu(eff) = 3.3 mu(B)/Pr which is comparable to a calculated value of 3.58 mu(B)/Pr for a free Pr3+ ion and a Weiss temperature, theta(cw) = 15.70 K indicating a dominant ferromagnetic interaction. From the analysis of M(B,T) and the 4f-electron derived specific heat (C-4f (T)) results, the CEF ground state is a Gamma(5) magnetic triplet and the CEF energy scheme is presented. The Sommerfeld coefficient, gamma estimated from the low-temperature C-4f (T) is 304 mJ/(mol K-2) indicating a mass enhancement of the conduction electrons at low temperatures. Further analysis of the heavy fermion properties based on the Sommerfeld-Wilson ratio supports the formation of a heavy fermion state in PrCu2Au3. However, the absence of an enhancement in S/T at low temperatures possibly suggests a weak correlation between the conduction electrons and the 4f-electrons at the Fermi energy. The thermal transport properties suggest that PrCu2Au3 is likely a compensated metal. (C) 2020 Elsevier B.V. All rights reserved.

We investigate the emergence of quantum critical points near a two-channel Kondo phase by evaluating an f-electron entropy of a seven-orbital impurity Anderson model hybridized with three (Gamma(7) and Gamma(8)) conduction bands with the use of a numerical renormalization group method. First we consider the case of Pr3+ ion, in which quadrupole two-channel Kondo effect is known to occur for the local Gamma(3) doublet state. When we control crystalline electric field (CEF) potentials so as to change the local CEF ground state from Gamma(3) doublet to Gamma(1) singlet or Gamma(5) triplet, we commonly observe a residual entropy of log. with the golden ratio phi = (1 + root 5)/2, which is equal to that for three-channel Kondo effect. This peculiar residual entropy is also observed for the case of Nd3+ ion, in which magnetic two-channel Kondo phase is found to occur for the local Gamma(6) doublet state. We envisage a scenario that the quantum critical point characterized by log. generally appears between two-channel Kondo and Fermi-liquid phases.