Electrical and thermal transport properties of RECu4AuRECu4Au compounds, RE=Nd, Gd

• A survey of electric and charge transport of magnetic and physical phenomena among the two rare-earth compounds RECu4Au (RE=Nd, Gd).
• Antiferromagnetic ordering at low temperatures was confirmed for both compounds. We are of the view that this work will lead to follow-up studies using single crystal material, in part with the purpose of resolving the unusual behavior we have found in the electrical resistivity of both compounds below their magnetic phase transitions.

We report the electrical and thermal transport properties of NdCu4AuNdCu4Au and GdCu4AuGdCu4Au compounds, crystallizing in the cubic MgCu4SnMgCu4Sn - type crystal structure, with space group F4¯3m (no. 216).These properties are reported through measurements of electrical resistivity, ρ(T)ρ(T), thermoelectric power, S(T)S(T) and thermal conductivity, λ(T)λ(T). ρ(T)ρ(T) and S(T)S(T) data indicate an antiferromagnetic (AFM)-like anomaly associated with a Néel temperature TN=3.9 K and 10.9 K for NdCu4AuNdCu4Au and GdCu4AuGdCu4Au compounds, respectively. ρ(T)ρ(T) data for both compounds shows a sudden drop at TN. Above TN, ρ(T)ρ(T) results are characteristic of an electron–phonon interaction in the presence of s−ds−d scattering. Application of magnetic field slightly suppresses TN value in GdCu4AuGdCu4Au compound from TN=10.9 K in a field of 0 T to 10.1 K in a field of 6 T. S(T)S(T) data at low temperatures for both compounds shows a minimum at TN. Critical analysis of S(T)S(T) in terms of the phenomenological resonance model yield the positions (Ef) and bandwidths (Wf) of the 4f - band in both compounds: Ef=3.81(6)K, Wf=329(58) K for the Nd compound and Ef=18.2(4) K, Wf=306(5) K for the Gd compound. λ(T)λ(T) for both compounds decreases linearly upon cooling from room temperature. The reduced Lorentz number L/L0L/L0 deviates from the Wiedmann–Franz at low temperature with a strong increase in L/L0L/L0 upon cooling the samples from room temperature.