Effect of doping on the ground-state spin of stacked organometallic ferromagnets

The effective Hamiltonians that describe the low-lying energy states of som e stacked organometallic ferromagnets with dopants have been derived. It is shown that the lattice stack with N unit cells and p conduction electrons has the ground-state spin S-0 = (N + p)/2 at p < N and S-0 less than or equ al to (3N - p)/2 at N less than or equal to p < 2N. This means that the fer romagnetic ground state of metallocene-based donor-acceptor stack is unstab le to the donor doping and is stable to the acceptor doping. (C) 1999 John Wiley & Sons, Inc.