Specific heat of superconducting indium in porous Vycor glass

Thermal measurements were made on indium-impregnated 5.6 nm Vycor glass at low temperatures in applied magnetic fields up to 1 Tesla. The indium lattice specific heat is enhanced relative to the bulk value, while the electronic contribution was unchanged. A slightly broadened superconducting transition with a bulk-like specific heat discontinuity indicate that the indium nanoparticles are strongly coupled. The phase diagram and size of the specific heat jump at Tc(H) yield κ ≈ 15. A field-periodic magnetocaloric effect has also been observed which may be related to flux depinning in the superconducting network.