The basic exchange interactions will be discussed for a variety of (R, T) compounds, in particular
RT2 (R: rare earth, or Y; T: transition metal). A magnetic phase diagram for (R, Y)Co2 compounds is
derived. The combined effect of the volume and the molecular field caused by the rare-earth spins is
demonstrated on R(Co, Fe)2, (R, Y)Co2, R(Co, Al)2 and R(Co, Cu)2, with an emphasis on the
metamagnetic transition in the 3d-subsystem. ?? 1992.