Coupling Strength between Superconducting Sn Fine Particles in Deposited Layer

抄録

For deposited layers of Sn fine particles as metal soot evaporated in inert gas, the superconducting critical field H_c and the transition temperature T_c were obtained by measuring their dc resistance. The temperature dependence of H_c is explained with the model of the cubic array of particles coupled through the Josephson junction. The coupling strength between the particles determined in this model decreases with increasing the particle size. This is supported by the thermogravimetric analysis where the thickness of the surface oxidized layer of the particle increases with increasing particle size. The enhancement of T_c is independent of the coupling between the particles, and depends only on the surface phonons of the particle.