Magnetic Field Tuned Superconductor-Weak-Insulator Transition in Indium Oxide Thin Film

It is well known that amorphous Indium Oxide thin films can undergo superconductor-insulator transitions by tuning the magnetic field, disorder, or charge density. In some cases intermediate metallic states have also been observed. We have studied amorphous Indium Oxide thin films grown by electron-beam evaporation in the presence of oxygen. Some samples appear to undergo a superconductor-weak-insulator transition (SWIT) as the applied magnetic field is varied. Sheet resistance measurements have shown superconductivity below a critical field and a weakly insulating state above. The resistance of this weakly insulating state saturates as the magnetic field is increased. The crossing of measured magnetoresistance isotherms has indicated a temperature dependent critical field. Additional measurements and scaling analysis may provide more details on the nature of this transition.