THE SPIN-3 2 BLUME-CAPEL MODEL ON A HONEYCOMB LATTICE/

The temperature dependences of the magnetization m = [[S]](r) and of t he moments q = [[S-2]](r) and r = [[S-3]](r) in the spin-3/2 Blume-Cap el model on a honeycomb lattice are examined in detail, within the fra mework of an effective field theory based on the use of a probability distribution that correctly accounts for the single site kinematic rel ations. A number of characteristic behaviours for their thermal Variat ions are obtained, especially for negative Values of the crystal field . Its phase diagram is obtained; besides a second-order transition lin e occurring at high temperatures, the phase diagram exhibits a first-o rder transition line separating the phases (3/2, 3/2) and (1/2, 1/2).