Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nanoscale Texture and Microstructure in NdFeAs(O,F)/IBAD-MgO
  Superconducting Thin Film with Superior Critical Current Properties   This paper reports the nanoscale texture and microstructure of a
high-performance NdFeAs(O,F) superconducting thin film grown by molecular beam
epitaxy on a textured MgO/Y$_2$O$_3$/Hastelloy substrate. The NdFeAs(O,F) film
forms a highly textured columnar grain structure by epitaxial growth on the MgO
template. Although the film contains stacking faults along the $ab$-plane as
well as grain boundaries perpendicular to the $ab$-plane, good superconducting
properties are measured: a critical temperature, $T _{\rm c}$, of 46 K and a
self-field critical current density, $J_{\rm c}$, of $2 \times 10^6 \,{\rm
A/cm^2}$ at 4.2 K. Automated crystal orientation mapping by scanning precession
electron diffraction in transmission electron microscopy is employed to analyze
the misorientation angles between adjacent grains in a large ensemble (247
grains). 99% of the grain boundaries show in-plane misorientation angles
($\Delta \gamma$) less than the critical angle $\theta_{\rm c}$, which
satisfies one of the necessary conditions for the high $J_{\rm c}$. Comparing
the columnar grain size distribution with the mean distance of the flux line
lattice, the triple junctions of low-angle grain boundaries are found to be
effective pinning centers, even at high temperatures ($\ge$35 K) and/or low
magnetic fields.

29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys