Impedance of Single-Walled Carbon Nanotube Fibers

Impedance measurements of single-wall carbon nanotube (SWCNT) fibers were carried out in the frequency range of 20-10(6) Hz at temperatures 4.2 < T < 300 K and in the range of applied bias voltage 0-5 V. It was found that in the low frequency range (f similar to 1-20 kHz) at low temperatures and at bias voltage U > 2 V sign of the imaginary part of impedance was changed from negative to positive, indicating the existence of the crossover from capacitive reactance to inductive one. This crossover was induced by the decrease of height of the energy barriers between nanotubes at the increase of bias voltage. As a result decrease of the impedance of the fibers is accompanied by the rising of the role of kinetic inductance of separate nanotubes.