We report on the observations of ferromagnetic spin polarized moment and superconductivity in Sn nanoparticles. Ferromagnetic spin polarization, which is characterized by the appearance of Langevin magneticfield profiles for magnetization, persists even at room temperature. At temperatures below 15 K, magnetic hysteresis emerges in the weak applied magnetic-field regime. Enhanced superconductivity is found for particles with diameters smaller than 16 nm but larger than 9 nm. The presence of a magnetic field in the superconducting phase reveals a regime in which the magnetic susceptibility and magnetization increase with decreasing temperature. We attribute these behaviors to the coexistence of ferromagnetic spin polarized moment and superconductivity at low temperatures.

An In nanoparticle powder was fabricated by employing the thermal evaporation method. Size analysis using x-ray diffraction profiles analysis and atomic force microscopy images indicates an average particle diameter of 36(2)nm and a Gaussian size distribution with a half-width of 3nm. The superconducting critical temperature of the In nanopowder increases slightly to 3.57(3)K, which was found to be extremely insensitive to the applied magnetic field. The critical magnetic field reaches ∼5T, which is a factor of 170 times higher than that of bulk In.