DESTRUCTION OF LOCALIZED ELECTRON PAIRS ABOVE THE MAGNETIC-FIELD-DRIVEN SUPERCONDUCTOR-INSULATOR TRANSITION IN AMORPHOUS IN-O FILMS

The field-induced superconductivity-destroying quantum transition in a morphous indium oxide films are investigated at low temperatures down to 30 mK. It is found that, on the high-field side of the transition, the magnetoresistance reaches a maximum and the phase can be insulatin g as well as metallic. With further increase of the magnetic field the resistance of the film drops and in the high-field limit approaches t he resistance value at the transition point, so that at high fields th e metallic phase occurs for both cases. We give a qualitative account of this behavior in terms of field-induced destruction of localized el ectron (C) 1998 American Institute of Physics. pairs. [S0021-3640(98)0 1716-2].