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Anisotropic Superconducting Devices

IP.com Disclosure Number: IPCOM000121238D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Koch, RH: AUTHOR [+2]

Abstract

Superconducting oxides of the YBaCuO composition (1-2-3) have been made which are superconducting to temperatures of about 95oK. This compound can be made in either thin film or bulk form. The devices disclosed herein can be made from either form and from similar materials such as T1- and Bi-based high Tc superconductors. The key element is the anisotropic properties of this type of material. The 1-2-3 compound forms in the orthorhombic structure with the long axis of the basic cell about 1.17 nm (c-axis) and the basal plane dimension of about 0.38 nm (ab plane, neglecting small differences in a and b dimensions). It has been shown that these samples have high critical currents in the ab plane and that the critical current can be a factor of ten or more lower in the c direction.

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Anisotropic Superconducting Devices

      Superconducting oxides of the YBaCuO composition (1-2-3)
have been made which are superconducting to temperatures of about
95oK.  This compound can be made in either thin film or bulk form.
The devices disclosed herein can be made from either form and from
similar materials such as T1- and Bi-based high Tc superconductors.
The key element is the anisotropic properties of this type of
material. The 1-2-3 compound forms in the orthorhombic structure with
the long axis of the basic cell about 1.17 nm (c-axis) and the basal
plane dimension of about 0.38 nm (ab plane, neglecting small
differences in a and b dimensions).  It has been shown that these
samples have high critical currents in the ab plane and that the
critical current can be a factor of ten or more lower in the c
direction.  Similarly, the critical magnetic fields are also
anisotropic.  Recent work has also shown that the energy gaps which
are important for tunnel junctions are also anisotropic.  Thus, this
material has different properties, depending on the direction in the
sample.  Novel devices and device concepts are disclosed which
utilize these properties.

      Consider a rectangular solid of almost square cross section
(basal plane) representing a crystal of macroscopic size of the 1-2-3
orthorhombic material.  In actual practice, an exact crystallite is
not required and the sample need only have a preferred orientation.
Electrical connections are attached to the sample so that the
electrical characteristics can be measured either in the...