The phase diagram of superconducting $U\!Pt_{ 3}$ in pressure-temperature plane, together with the neutron scattering data is studied within a two component superconducting order parameter scenario. In order to give a qualitative explanation to the experimental data a set of two linearly independent antiferromagnetic moments which emerge appropriately at the temperature \mbox{ $T_{ N}\sim 10\cdot T_{ c}$} and \mbox{ $T_{ m}\sim T_{ c}$} and couple to superconductivity is proposed. Several constraints on the fourth order coefficients in the Ginzburg-Landau free energy are obtained.
Categories: cond-mat