Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Interpretation of large room-temperature diamagnetism at low magnetic
  fields in films of oxidised atactic polypropylene in terms of superconducting
  current loops   A simple model is used to analyse published results on large room-temperature
diamagnetism for two films of oxidised atactic polypropylene (OAPP) at low
magnetic fields. The model involves induced currents expected in circular
closed loops of superconductors in fields below the lower critical field H_{c1}
at which flux penetration would first occur if a metamagnetic transition did
not intervene as in OAPP, and the assumption that resistance would be restored
at H_{c1} (negligible pinning). Fits to the data for the more strongly magnetic
sample with the model, allowing two different types of loops with different
loop radii b_1 and b_2, but with the same cross section a of loop material
yield H_{c1} is approximately equal to 5260 Oe, and fits to the data for the
less strongly magnetic sample with two loop sizes and with the same value of
H_{c1}, combined with the knowledge that the minimum number of closed loops of
any type is one, requires that the radius a of the cross section of the
material should be less than about 0.8 micrometres, in fair agreement with a
maximum radius of 1 micrometre obtained previously from other data.

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The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph