Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Change of surface critical current in the surface superconductivity and
  mixed states of superconducting Niobium   A systematic study of irreversible magnetization was performed in bulk
Niobium after different surface treatments. Starting with smooth surfaces and
abrading them, a strong increase of the critical current is observed up an
apparent limiting value. An impressive change of the critical current is also
observed in the surface superconductivity (SSC) state, reaching values of the
same order of magnitude as in the mixed state. We explain also the observation
of strong SSC for magnetic field perpendicular to larges facets in terms of
nucleation of SC along bumps of a corrugated surface.

31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex