Theoretical Study of Pressure Effect on TDAE-C60

We have theoretically studied pressure effects on molecular ferromagnet C$_{60}$ complexes with tetrakis (dimethylamino) ethylene (TDAE), particularly the pressure-induced depression of the Curie temperature. The observed behavior is well simulated with our model based on a charge transfer induced intramolecular Jahn-Teller distortion and an intermolecular cooperative Jahn-Teller interaction. We emphasize that the theoretical simulation is carried out with reasonable parameters known for C$_{60}^-$ complexes. It is concluded that the enhancement of crystal field at C$_{60}$ site due to increasing pressure causes the depression of Curie temperature.