Estimation of pi d-interactions in organic conductors including magnetic anions

Magnetic interactions in organic conductors including magnetic anions, such as lambda-(BETS)(2)FeCl4 and kappa-(BETS)(2)FeX4 [X = Cl and Br], are estimated from intermolecular overlap integrals; the overlaps between anions afford J(dd), and those between anions and donors give J(pid). From this, the most stable spin alignments are decided, and such quantities as the Neel and Weiss temperatures, as well as the magnitude of spin polarization on the pi-molecules are evaluated on the basis of the mean-field theory of pid-systems. The calculation is extended to several other pid-conductors, which are classified depending on the relative magnitudes of the direct dd- and indirect pid-interactions.