Biomagnetic Technologies, Inc.

Kai-Yueh Yang

Mark S DiIorio

Shozo Yoshizumi

A superconductor device has a substrate with an inclined surface that divides the substrate surface into a lower planar substrate surface and an upper planar substrate surface. A lower layer of an anisotropic superconductor material is epitaxially deposited on the lower planar substrate surface so that an a-axis of the anisotropic superconductor material of the lower layer is exposed at a top edge of the lower layer. An upper layer of an anisotropic superconductor material is epitaxially deposited on the upper planar substrate surface so that an a-axis of the anisotropic superconductor material of the upper layer is exposed at a top edge of the upper layer. A layer of a non-superconductor material overlies the inclined surface and the layers of anisotropic superconductor material.

Microbridge superconductor device utilizing stepped junctions

A cooling apparatus includes a dewar and a quantity of liquid nitrogen within the container. Gaseous helium is contacted to the liquid nitrogen, either by contacting its top surface or by being bubbled through the liquid nitrogen. The temperature of the cryogenic liquid is lowered by the contact of the gas.

Cooling using a cryogenic liquid and a contacting gas

A microbridge superconductor device includes a substrate, made of a material such as LaAlO.sub.3, having a lower planar substrate surface, an inclined surface having an overall upward inclination of from about 20 to about 80 degrees from the plane of the lower planar substrate surface, and an upper planar substrate surface parallel to the lower planar substrate surface and separated from the lower planar substrate surface by the inclined surface. A layer of a c-axis oriented superconductor material, made of a material such as YBa.sub.2 Cu.sub.3 O.sub.7-x, is epitaxially deposited on the lower planar substrate surface, and has an exposed a-axis edge adjacent the intersection of the lower planar substrate surface with the inclined surface. The a-axis exposed edge is beveled away from the intersection. A layer of a c-axis oriented superconductor material is epitaxially deposited on the upper planar substrate surface, and has an exposed a-axis edge adjacent the inclined surface. A gap lies between the two a-axis exposed edges. A layer of a non-superconductor material, such as silver, lies in the gap between the two exposed a-axis edges, thereby defining a SNS superconductor microbridge device. The layers of superconductor material are preferably patterned to form a Josephson junction device such as a superconducting quantum interference device.

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San Diego, CA, United States of America

Kai-Yueh Yang