Metal-insulator transition and novel magnetoresistance effects in amorphous carbon films

Amorphous carbon films were successfully prepared by radio frequency magnetron sputtering at different deposition temperatures. We observed metal-insulator transition in the amorphous carbon films, and found that the metal-insulator transition temperature moved to low temperature with the increase o...

Full description

Saved in:
Bibliographic Details
Published in:Carbon (New York) 2019-07, Vol.148, p.512-517
Main Authors: Liu, Zhichao, Zhen, Congmian, Wang, Peiyu, Wu, Chunfang, Ma, Li, Hou, Denglu
Format: Article
Language:English
Subjects:
Antiferromagnetism
Carbon
Deposition
Domains
Ferromagnetic phases
Ferromagnetism
Giant magnetoresistance
Insulation
Insulators
Magnetism
Magnetoresistance
Magnetoresistivity
Magnetron sputtering
Metal-insulator transition
Radio frequency
Sandwich structures
Temperature
Thin films
Transition temperature
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Amorphous carbon films were successfully prepared by radio frequency magnetron sputtering at different deposition temperatures. We observed metal-insulator transition in the amorphous carbon films, and found that the metal-insulator transition temperature moved to low temperature with the increase of the deposition temperature. A local sandwich structure formed by sp2 and sp3 hybridized carbon domains was thought to exist in the amorphous carbon films, which is responsible for the negative giant magnetoresistance of the film. Ferromagnetism and antiferromagnetism coexist in the localized sandwich structure, and they are tuned by temperature and external magnetic field, resulting in a small bulge and signal reversal of the magnetoresistance of the film. The proportion of sp2 and sp3 hybridized carbon in the carbon films can be adjusted by temperature. Different bonding configurations of sp2 and sp3 hybridized carbon result in two kinds of unpaired electrons, thus exhibiting two ferromagnetic phases. [Display omitted]
ISSN:0008-6223
1873-3891
DOI:10.1016/j.carbon.2019.04.027