Hydrothermal fabrication and superconductivity of isotropic Pb hollow microspheres

• Isotropic Pb hollow microspheres have been prepared by the hydrothermal process
• The multicrystal hollow microspheres were high purity and well-crystallized.
• Magnetic measurements reveal these as-fabricated products are superconducting with an onset Tc 11.05 K, which is a little higher than Tc of counterpart bulk sample (7.19 K).

In this work, we report a facile solvothermal route for synthesis of multi-crystalline isotropic Pb hollow sphere-like samples. In the absence of any template and catalyst, large-scale uniform Pb hollow microspheres with an inside diameter of 400 nm have been produced. The products are detected by electron microscopy, X-ray diffraction/photoelectron energy spectroscopy. Magnetic measurements reveal these as-fabricated specimens are superconducting with an onset Tc 11.05 K, which is 3.86 K above the bulk Tc (7.19 K). Superconducting Pb hollow microspheres with the high Tc may open up new possibilities for the fundamental understanding of the effect of dimensionality and superconducting mechanism.