Non-linear annealing effect on correlation between crystallinity and oscillation of carbon nanocoils

The effect of annealing at 1000-2600 °C on the crystallinity of carbon nanocoils (CNCs) has been evaluated to discuss the mechanism of energy dissipation during CNC oscillation and its structural dependence. The crystallinity of the CNCs was evaluated by transmission electron microscopy and electron diffraction. In situ observations of the resonant oscillations of individual cantilevered-CNCs were carried out by inducing a high-frequency electric field in a scanning electron microscope. Experimental results revealed a non-linear correlation between crystallinity and oscillation properties; crystallinity improved with annealing temperature from 1000to2600°C and was comparable to graphite on annealing at 2600 °C, while the quality factor (Q) decreased on annealing above 1400 °C. Q showed a strong correlation with the shear modulus. These results suggest that the oscillation properties of CNCs are dominated by two types of energy dissipation mechanisms, originating in the existence of structural anomalies in less crystalline structures and in interlayer slipping in higher crystallinity structures.