International Business Machines Corporation

Gregory John Clark

Richard Joseph Gambino

Robert B Laibowitz

Roger Hilsen Koch

Corwin Paul Umbach

Allan David Marwick

Jerome J Cuomo

James L Speidell

Praveen Chaudhari

Stanley Irwin Raider

Robert E Drake

Margaret A Frisch

A superconducting device operable at temperatures in excess of 30&#xb0; K. and a method for making the device are described. A representative device is an essentially coplanar SQUID device formed in a single layer of high Tsuperconducting material, the SQUID device being operable at temperatures in excess of 60&#xb0; K. High energy beams, for example ion beams, are used to convert selected portions of the high Tsuperconductor to nonsuperconductive properties so that the material now has both superconductive regions and nonsuperconductive regions. In this manner a superconducting loop having superconducting weak links can be formed to comprise the SQUID device.

Method for making a superconductor device

A superconducting device operable at temperatures in excess of 30.degree. K. and a method for making the device are described. A representative device is an essentially coplanar SQUID device formed in a single layer of high T.sub.c superconducting material, the SQUID device being operable at temperatures in excess of 60.degree. K. High energy beams, for example ion beams, are used to convert selected portions of the high T.sub.c superconductor to nonsuperconductor properties so that the material now has both superconductive regions and nonsuperconductive regions. In this manner a superconducting loop having superconducting weak links can be formed to comprise the SQUID device.

Devices using high T.sub.c superconductors

A spherical grid for use in instrumentation comprising a rigid non-magnetic frame having a pattern of holes. Into each hole a flat wafer is placed, each wafer having etched therein holes defining the grid mesh. The frame maintains the geometric conformal shape allowing large units to be constructed.

Spherical retarding grid analyzer

A method for trimming the zero voltage Josephson current of a tunnel junction including the steps of measuring the I-V characteristics of the completed junctions to quantify the change in I.sub.o necessary to meet the design requirements, placing the tested Josephson junctions on a metal block which is mounted in the sample chamber of an ion implanter structure which is pumped to 1.10.sup.-6 Torr. The junctions, kept at room temperature and oriented at a direction nearly normal to the ion beam, are implanted with magnetically analyzed ions of energies 50 keV to 2300 keV. Spatial uniformity of the ion implant beam is .+-.2% over a sample. Uniform spatial implantation over a large area sample is obtained by either sweeping of the beam across the sample, or restoring the sample through a stationary beam, determining the required ion dose to effect trimming from calibration curves, remeasuring the I-V characteristics after implantation to confirm that the required I.sub.o trim was effected, and then completing the fabrication of the Josephson device according to standard processing.

Adjustment of Josephson junctions by ion implantation

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Katonah, NY, United States of America

Gregory John Clark