Measurements of superconducting transition temperature Tc of Sn nanoparticles

A direct measurement of the superconducting transition temperature Tc by ac susceptibility in 15 nm Sn nanoparticles shows that Tc decreases with increasing applied magnetic fields. A London penetration model based on small nanoparticles was used to evaluate a quantitative relationship between the applied magnetic fields Ha and Tc. Significant changes, compared to their corresponding bulk values, in superconducting properties such as shorter London penetration depth, higher zero field critical temperature, and much higher zero temperature critical field were clearly observed in this work.