Speaker
Description
We report on the PVD deposition of Nb3Sn
on Cu substrates with and without a thick Nb interlayer to
produce Cu/Nb/Nb3Sn and Cu/Nb3Sn multilayer structures.
The Nb3Sn was sputtered directly from an alloy target
at room and elevated temperatures. The dependence of
the superconducting properties of the total structure on
deposition parameters has been determined. The films have
been characterized via SEM, XRD, EDX and SQUID magnetometer
measurements. Analysis showed that the composition
at both room and elevated temperature was within
the desired stoichiometry of 24–25 at%. However, superconductivity
was only observed for deposition at elevated
temperature or post annealing at 650 °C. The critical temperature
was determined to be in the range of 16.8 to 17.4
K. In the case of bilayer deposition, copper segregation
from the interface all the way to the surface was observed.
