Spin-transfer mechanism of ferromagnetism in polymerized fullerenes: $Abinitio$ calculations

A mechanism of the high temperature ferromagnetism in polymerized fullerenes is suggested. It is assumed that some of the C${}_{60}$ molecules in the crystal become magnetically active due to spin and charge transfer from the paramagnetic impurities (atoms or groups), such as hydrogen, fluorine, hydroxyl group OH, amino group NH${}_2$, or methyl group CH${}_3$, dispersed in the fullerene matrix. The exchange interaction between the spins localized on the magnetically active fullerenes is evaluated using $\mathit{\text{ab}}\mathit{\text{initio}}$ calculations. The nearest neighbour and next nearest neighbour exchange interaction is found to be in the range $0.1÷0.3$ eV, that is, high enough to account for the room temperature ferromagnetism.