Small capacitance self-shunted MoRe–Si(W)–MoRe junctions for SQUIDs applications

MoRe–Si(W)–MoRe planar Josephson junctions with a hybrid barrier layer made of amorphous silicon doped with tungsten at relatively high tungsten concentrations (~ 11%) are experimentally studied. Small intrinsic (natural) capacitance and shunting by tungsten nanoclusters give an advantage to MoRe–Si(W)–MoRe junctions against traditional superconductor–insulator–superconductor (SIS) planar junctions as candidates for innovative superconducting electronics. It is shown that the use of such junctions with a Si(W) barrier layer thickness of 15–30 nm can substantially enhance the sensitivity of both RF and DC SQUIDs.