Giant negative magnetoresistance of semi-insulating amorphous indium oxide films in strong magnetic fields

Access to files

Full-text and supplementary files are not available from Manchester eScholar. Full-text is available externally using the following links:

Abstract

We have studied magnetoresistance in thin films of amorphous indium oxide with various degrees of oxidation, i. e., with various densities of states in the vicinity of the Fermi level. A large negative magnetoresistance is observed when the films are in the insulating state. The negative field derivative partial derivative R/partial derivative H of the resistance persists up to 20 T, the highest magnetic field in our experiment. The magnetoresistance is described in terms of a field-dependent gap at the Fermi level. Such a gap can arise due either to tunneling in a system of fluctuation-induced superconducting clusters or to the Cooper interaction between electrons localized in shallow minima of the random potential. In the latter case, if the depth of the minima is smaller than the Debye energy, the electrons are virtually delocalized by short-wavelength phonons.

Keyword(s)

conductivity; dependence; hopping magnetoresistance; samples; superconductivity; transition

Bibliographic metadata

Institutional metadata

Record metadata