Magnetic Torque in k-(BETS)2Mn[N(CN)2]3

Peculiarities observed in the field dependencies of the magnetic torque in k-(BETS)2Mn[N(CN)2]3 measured at T=1.5K, H=0-150kOe, have been explained from the viewpoint of the two interacting spin subsystems, one associated with d-electron spins of Mn2+ residing in the anion layer, and the other with the spins of pi-electrons which localize below the metal-insulator transition temperature, T_MI=25K, forming a long-range antiferromagnetic structure. The principal axes of the Mn2+ spin subsystem have been defined. A model of antiferromagnetic pi-spin arrangement has been suggested that associates the observed kinks in the torque H-dependencies with a spin-reorientation transition. One of the observed effects is ascribed to the pi-d interaction between the two spin subsystems.