  In the organic charge transfer salt k-(BETS)2Mn[N(CN)2]3 the metallic
conductivity is provided by itinerant pi-electrons in the layers of BETS
molecules, whereas magnetization is largely dominated by the localized
d-electrons of the Mn2+ ions in the insulating anionic layers. We study
magnetic properties of the compound in its low-temperature, Mott-insulating
state by means of magnetic torque technique. The complex behavior of the torque
can be qualitatively explained by the coexistence of two weakly interacting
magnetic subsystems associated with paramagnetic d-electron spins and
antiferromagnetically ordered pi-electron spins, respectively. Based on the
experimental data, we determine the principal axes of magnetization of the Mn2+
sublattice and propose a qualitative model for the pi-electron spin
arrangement, implying an important role of the Dzyaloshinskii-Moriya
interaction.
