The Effect of Diluted Water Treatments on the Superconducting Properties of $\hbox {MgB}_{2}$

To examine the effect of diluted water treatments on the superconducting properties of MgB₂, MgB₂ powders were prepared by mixing with a series of diluted water (water-ethanol mixture). XRD analyses were carried out to investigate the phases of the diluted water-treated MgB₂ powders. Both the isothermal magnetizations M(H) of the series of samples at fixed temperature and M(T) in fixed field, employing a PPMS-9 (Quantum Design), were measured. The degradation of the superconductivity of MgB₂ by the diluted water treatments was observed. The diluted water-treated MgB₂ powders have shown reduced superconductivity as the water concentration in the diluted water increases.