Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Grain boundary characteristics of oxypnictide NdFeAs(O,F)
  superconductors   We have systematically investigated the grain boundary (GB) angle dependence
of transport properties for NdFeAs(O,F) fabricated on [001]-tilt symmetric MgO
bicrystal substrates. In our previous study, NdFeAs(O,F) bicrystal films showed
a weak-link behaviour even at a GB angle of 6{\deg}. However, this was caused
by an extrinsic effect originating from the damage to both NdFeAs(O,F) and MgO
substrate by excess F-diffusion along the grain boundary. To investigate the
intrinsic nature of grain boundaries, we minimized the damage to NdFeAs(O,F)
and MgO by reducing the deposition temperature of NdOF over-layer needed for
F-doping. The resultant NdFeAs(O,F) bicrystal films have a critical angle of
8.5{\deg}, above which Jc starts to decrease exponentially. This critical angle
is almost the same as those of other Fe-based superconductors.

11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas