Physical-Chemical Vapor Deposition Process"
Inventors: Xiaoxing
Xi, et al.
PSU Invention Disclosure No.
2003-2869
Licensing Contact: Matthew
D. Smith
FIELD OF INVENTION
Superconductivity, electric power and high field magnets
DESCRIPTION OF INVENTION
MgB2 thins films were doped
with carbon during the Hybrid Physical Chemical Vapor Deposition (HPCVD) process.
The films were deposited at a temperature under 750oC and at a thickness
of up to 4000 Angstroms. The residual resistivity increases rapidly while Tc
decreases much more slowly with carbon doping. The critical current density
in magnetic field increases dramatically from that in the clean film due to
stronger vortex pinning. For example, with a nominal carbon concentration of
24 at.%, the residual resistivity increases from the undoped value of less than
1 mWcm to 200 mWcm, but Tc only decreases
from over 41K to 35K, and Hc2(0) increases to 70 T. For a film doped
with 7.4 at.% nominal carbon concentration, at 25 K Jc remains well
above 105 A/cm2 at 4 T. Structurally, the doped films
are textured with nano-grains and highly resistive amorphous areas at the grain
boundaries. The doped films have comparatively weak anisotropy. The results
demonstrate that the carbon doping approach may be used to enhance Hc2
and Jc(H) of MgB2 to make practical materials for high
magnetic-field applications.
UTILITY
The subject invention is a special technique
of doping MgB2 thin films to enhance the Hc2 and Jc(H).
The inventors believe that this technique can be modified to make doped MgB2
powder for the fabrication of wires or to make doped MgB2 coated
conductors. The market for this technology is believed to be, in the short
term, those industries that have already established themselves in cryogenics
and superconductivity. Such company would include those in the fields of medical
MRI magnets, magnets for high energy accelerators, high magnetic field facilities
and laboratory magnets. In terms of a longer time horizon, the inventors envision
that this technology could have applications in electric power cables, superconducting
magnetic energy storages, motors, generators, etc.
INVENTION STATUS
The invention arose from federal funding.
The inventors continue to conduct additional research under said funding sources.
U.S. Patent Application No. 10/395,892 and PCT/US03/08770 are pending on certain
aspects of the HPCVD process (PSU Invention Disclosure No. 2002-2616).