Magnetization under high-pressure in organic ferromagnet α-TDAE-C60

The magnetization measurements under pressure were performed on the fullerene-based ferromagnet, α-TDAE-C60. We found that the saturation magnetization below the ferromagnetic ordering temperature Tc is rapidly suppressed with increasing pressure and disappeared above Pc2=0.1-0.2GPa. This pressure is remarkably lower than the critical pressure of polymerization Pc=0.7GPa. On the contrary, Tc is almost pressure independent below Pc2, but, above Pc2, could not be entirely determined because of the strong suppression of the magnetization. In the paramagnetic region, the susceptibility under pressure indicates the total number of spins remains unchanged around Pc2 as well as Pc. We discuss these results compared with the high-pressure ESR