Superconductivity in self-flux-synthesized single crystalline R₂Pt₃Ge₅(R = La, Ce, Pr)

In order to study the basic superconductivity properties of Pr₂Pt₃Ge₅, we synthesized the single crystalline samples by the Pt-Ge self-flux method. R₂Pt₃Ge₅ (R = La, Ce) were also grown for a systematic study. Zero-resistivity was observed in both the La- and Pr-based samples below the reported superconducting transition temperatures. However, magnetic susceptibility measurements showed low superconductivity volume fractions in both La₂Pt₃Ge₅ and Pr₂Pt₃Ge₅ (less than 2%). Ce₂Pt₃Ge₅ did not show any signature of superconductivity. From the specific heat measurements, we did not observe a superconducting transition peak in Pr₂Pt₃Ge₅, suggesting that it is not a bulk superconductor. The magnetic susceptibility and heat capacity measurements revealed two antiferromagnetic (AFM) orders in Pr₂Pt₃Ge₅ at T_N1 = 4.2 K and T_N2=3.5 K, as well as a single AFM transition at T_N = 3.8 K in Ce₂Pt₃Ge₅.