CRITICAL PHENOMENA NEAR THE FINAL ORDERING PHASE-TRANSITION POINT IN DOUBLE MAGNETIC SYSTEMS

Magnetic crystals containing two subsystems of different types of magn etic ions are considered. It is assumed that the subsystem of the firs t type of ions is already ordered at a relatively high temperature, wh ile the ordering temperature of the second subsystem T(c2) is much low er. We carry out the analysis of the critical behavior of such double magnetic systems in the vicinity of the temperature T(c2). We find qui te different critical behavior for different symmetries of the subsyst em coupling.