2019/03/29 by Ogunbunmi, Michael O, Strydom, André M
#FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el)
paper · doi:10.48550/arxiv.1903.12362
We have synthesized PrPt4Ag and PrPt4Au compounds for the first time and report their crystal structure, as well as magnetic and physical properties in the temperature range of 1.9~K to 300~K. Both compounds are derived from the substitution of Pt with Ag and Au, respectively in the parent compound PrPt5 which crystallizes in the hexagonal CaCu5-type structure. Here we observed the preservation of the hexagonal CaCu5-type structure under such substitutions, which is in contrast to the observations in PrCu4Ag and PrCu4Au adopting the cubic MgCu4Sn-type structure upon substitution on parent hexagonal PrCu5. The temperature dependences of specific heat Cp(T), and electrical resistivity ρ(T) of PrPt4Ag show an anomaly at 7.6~K. This is absent in the magnetic susceptibility χ(T), thus suggesting a possible multipolar ordering of the Pr3+ moment. PrPt4Au on the other hand does not show any anomaly but an upturn in Cp(T)/T below about 10~K and attains 1.23~J/(mol K2) at 1.9~K. In addition, ρ(T) ∼ T for nearly a decade in temperature. These observations for PrPt4Au are the hallmark of a non-Fermi liquid (nFL) behavior and is characteristic of a system near a quantum critical point. The analyses of the low-temperature Cp(T) for PrPt4Ag and PrPt4Au give values of the Sommerfeld coefficient, γ= 728.5~mJ/(mol K2) and 509.1~mJ/(mol K2), respectively, indicating a significant enhancement of the quasiparticle mass in the two compounds.