  A recent proposal that the metamaterial approach to dielectric response
engineering may increase the critical temperature of a composite
superconductor-dielectric metamaterial has been tested in experiments with
compressed mixtures of tin and barium titanate nanoparticles of varying
composition. An increase of the critical temperature of the order of 0.15 K
compared to bulk tin has been observed for 40% volume fraction of barium
titanate nanoparticles. Similar results were also obtained with compressed
mixtures of tin and strontium titanate nanoparticles.
