Oxygen and hydrogen plasma effects on the MgB2 superconductivity

Oxygen and hydrogen plasma effects on the superconductivity in MgB2 were investigated. As a result, the critical current density was found to increase by the plasma treatments by an order of magnitude at zero applied magnetic field. The electrical resistivity showed a decrease in the superconducting transition temperature after the plasma treatments, whereas the magnetic susceptibility did not show a change in the transition temperature, indicating percolation of the supercurrent among the superconducting islands in the plasma-treated samples.