Structure dependent negative magnetoresistance of amorphous carbon thin films

Abstract

Negative magnetoresistance (MR) up to 13% was observed at 2K under the magnetic field of 7T in amorphous carbon thin films synthesized by chemical vapor deposition. No tendency of saturation of MR is observed up to the magnetic field of 7T. Shift of structural morphology from disordered amorphous carbon to ordered graphitic like carbon was studied by using Raman, X-ray Diffraction, High Resolution Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy. Negative MR effect increases with the increase in structural order. The mechanism of this negative MR could be ascribed to the Weak Localization and Grain Boundary Scattering Conduction depending on the different temperature regimes.