Magnetism of Superconducting UPt3

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.