Quenching induced enhancement of coupling between the molecule reorientation and grain boundary relaxation in polycrystalline C60
Abstract
Dielectric spectroscopy was performed on polycrystalline C60 powder at selected frequencies from 111 Hz to 2 MHz as the temperature rose from 100 K to 473 K. About 3 K increase of the first-order phase transition temperature caused by quenching was observed, but disappeared in the second heating cycle. The apparent activation energy of dipole relaxation in low temperature range increases to 387 ± 4 meV which is 19 meV higher than that of pristine C60. Meanwhile, a novel grain boundary (GB) relaxation was also found in the quenched C60. It is suggested that quenching increase the GB viscosity, which facilitates the coupling between the GB motion and C60 orientation jump.
- Publication:
-
Chemical Physics
- Pub Date:
- July 2020
- DOI:
- 10.1016/j.chemphys.2020.110784
- Bibcode:
- 2020CP....53510784W
- Keywords:
-
- Quenching;
- Disordered groups of atoms;
- Dipole relaxation;
- Grain boundary relaxation