Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Enhancement of the upper critical field of Nb3Sn utilizing disorder
  introduced by ball milling the elements   Nb3Sn was prepared by milling Nb and Sn powder mixtures followed by limited
reactions to restrict disorder recovery. Although disorder reduced the
superconducting critical temperature Tc, the concomitant electron scattering
increased the upper critical field mu0Hc2 to as high as 35 T at 0 K, as
determined by the Werthamer-Helfand-Hohenberg equation. Hc2 was higher for
longer milling times and lower annealing temperatures. Substitution of 2% Ti
for Nb did not appreciably enhance Hc2, suggesting that alloying mitigates the
benefits of disorder. Since alloyed Nb3Sn wires have mu0Hc2(0) approximately 29
T, wires based on heavily milled powders could extend the field range for
applications if they can be made with high current density.

33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph