Electrical and mechanical properties of C-70 fullerene and graphite under high pressures studied using designer diamond anvils

We compare electrical and mechanical properties of C-70 fullerene with high purity graphite to 48 GPa at room temperature using designer diamond anvil s with embedded electrical microprobes. The electrical resistance of C-70 s hows a minimum at 20 GPa with transformation to an amorphous insulating pha se complete above 35 GPa, while graphite remains conducting. Nanoindentatio n shows hardness values 220 times larger for the pressure quenched amorphou s phase than for similarly treated graphite. Our studies establish that the amorphous carbon phase produced from C-70 has unique properties not attain able from graphite.