Magnetoresistance and magnetic field induced metal–insulator transition in intercalated amorphous carbon

Abstract

In this work, we discuss the preparation of iodine and sulfur incorporated amorphous carbon (a-C) films by vapor phase pyrolysis technique. Iodine incorporated a-C films depict an unusual resistivity behavior at low temperatures, where a clear positive temperature coefficient (PTCR) is witnessed, which also depicts a pyrolysis temperature and iodine incorporation induced metal–insulator (M–I) transition. Magnetic field induced M–I transition is also observed in iodinated samples. Magnetoresistance measurements performed on these films from 1.3–10 K in the presence of magnetic field (0–7 T) account for a positive magnetoresistance irrespective of the regimes they fall in. Universal scaling of magnetoconductance observed in intercalated a-C system depicts the dominance of electron–electron interaction.