MAGNETIC-PROPERTIES OF C-60-TDAE AND TTFXC60BRY

The magnetic properties of C-60-TDAE and TTFxC60Bry may be described b y the multi-band extended Hubbard model and the local configuration in teraction method comparing the energy of the spin singlet and the spin triplet of a two-electron problem, Both the exchange and on site repu lsion interactions play important roles in magnetism, For the half-fil led single band system for most of the realistic lattice distances onl y antiferromagnetic long range order is allowed. For the C-60-TDAE and TTFxC60Bry systems, a multi-band description is more suitable. The co ndition of ferromngnetic long range order in a two-band system is give n, Ferromagnetism can occur in C-60-TDAE and TTFxC60Bry.