Comparison of bulk DC and microwave surface resistance of explosively fabricated Y-Ba-Cu-O and Bi-Pb-Sr-Ca-Cu-O metal-matrix composite superconductors

Abstract

Explosive (shock-wave) fabrication has been used to develop simple, monolithic planar sandwich arrays of superconducting YBa2Cu3O7 and Bi7Pb3Sr10Ca10Cu15Ox powder and powder mixtures in a copper matrix and in a complex metal composite of 6061-T6 aluminum, silver and copper. These bulk superconducting arrays have been scaled from planar sizes of 20*25 cm to 25*38 cm; with superconducting channel sizes ranging from 3 mm2 to 10 mm2 in cross section and exposed dipolar strips having areas greater than 1*25 cm. The as-fabricated arrays exhibited shock-wave induced degradation of superconductivity, with zero frequency resistances ranging from 1 to 0.6 k Omega , and microwave surface resistances ranging from 32 to 82 m Omega at 3 GHz and 77 K (liquid nitrogen temperature). Zero frequency superconductivity exhibiting zero resistance at 77 K was achieved by extracting both Y-Ba-Cu-O and Bi-Pb-Sr-Ca-Cu-O consolidated channel sections from the explosively fabricated metal-matrix monoliths and annealing them at high temperature in oxygen or air respectively. Corresponding microwave (3 GHz) surface resistances were then observed to be reduced to around 15 m Omega . The results illustrate the ability to fabricate and scale up a variety of bulk composite superconducting arrays having microwave antenna applications in light-weight structures as well as a host of other potential space applications.