Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First Order Transition of the Vortex Lattice in Disordered Bi-2212
  Crystals   Using differential magneto-optical imaging, we address the question of
mesoscopic inhomogeneity in underdoped Bi-2212 single crystals. Among other
features, it is shown that an anomalous temperature dependence of the
penetration field and of the first order transition (FOT) field of the vortex
lattice in such crystals can be understood as arising from inhomogeneity. The
effect of chemical inhomogeneity and pinning on flux penetration and the FOT is
discussed.

24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph