Coexistence between magnetism and superconductivity in the HgMn$_{0.3}$Pb$_{2}$ compound

In this work will be show the influence Mn doping in the HgPb$_{2}$ phase. The HgMn$_{0.3}$Pb$_{2}$ phase is investigated by x-ray diffraction, magnetic and electrical resistivity measurements. Polycrystalline samples with HgMn$_{0.3}$Pb$_{2}$ nominal compositions were prepared by solid state reaction. X-ray powder diffractograms suggest that all peaks can be indexed with the tetragonal phase of AuCu prototype. The R(T) data for the HgMn$_{0.3}$Pb$_{2}$ composition reveals superconductor behavior below 5.9K. The careful analysis of M(T) data reveals magnetic ordering close to 45K with saturation around the superconducting transition. The Mn doping in the HgPb$_{2}$ phase suggests the magnetic ordering it is occurring in the specific plane occupied by Mn atoms. The M(H) data show typical type-II superconductor which we estimate the H$_{C1}$ approximately 240 Oe. This work, report by first time the coexistence between magnetism and superconductivity in an AuCu prototype compound