Devices using high T.sub.c superconductors

A superconducting quantum interference device (SQUID) device operable at temperatures greater than 60.degree. K., said device comprising:

• a layer of high T.sub.c superconducting material capable of exhibiting superconductivity at temperatures greater than 60.degree. K.,
• implanted regions of said layer having a sufficiently damaged structure that said implanted regions are nonsuperconducting,
• nonimplanted regions of said layer which have high T.sub.c superconductivity and form a superconductivity loop, wherein said implanted and nonimplanted regions have substantially coplanar surfaces,
• wherein said implanted regions constrict the width of said loop in at least two locations therein, the constriction being sufficient to form weak links at each of said locations, wherein said superconducting loop including said weak links operates as a DC SQUID device when electrical currents exist therein at temperatures greater than 60.degree. K.

A multi-layer superconducting device structure operating at temperatures in excess of 40.degree. K., comprising:

• a first layer of material capable of material exhibiting superconductivity at temperatures greater than 40.degree. K.,
• first regions of said first layer which are rendered nonsuperconductive and second regions of said first layer which exhibit superconductivity at temperatures greater than 40.degree. K.
• a layer of nonsuperconductivity material located on said first layer, and
• a second layer of material capable of material exhibiting superconductivity at temperatures greater than 40.degree. K., first regions of said second layer which are rendered nonsuperconductive and second regions of said second layer which exhibit superconductivity at temperatures greater than 40.degree. K. said first and second superconductive layers having devices therein.

A SQUID device capable of operating at temperatures greater than 30.degree. K., said SQUID being comprised of:

• a layer of superconductive material having a transition temperature greater than 30.degree. K.,
• first regions of said material which are rendered nonsuperconductive,
• second regions of said material which exhibit superconductivity at temperatures in excess of 30.degree. K., said second regions forming a closed loop, and
• at least one weak superconductive link in said loop, said weak superconducting link being substantially planar.