Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Critical Currents, Pinning Forces and Irreversibility Fields in
  (YxTml-x)Ba2Cu3O7 Single Crystals with Columnar Defects in Fields up to 50 T   We have studied the influence of columnar defects, created by heavy-ion (Kr)
irradiation with doses up to 6 10^11 Kr-ions/cm2, on the superconducting
critical parameters of single crystalline (YxTm1-x)Ba2Cu3O7. Magnetisation
measurements in pulsed fields up to 50 T in the temperature range 4.2 - 90 K
revealed that: (i) in fields up to T the critical current Jc(H,T) is
considerably enhanced and (ii) down to temperatures T ~ 40 K the
irreversibility field Hirr(T) is strongly increased. The field range and
magnitude of the Jc(H,T) and Hirr(T) enhancement increase with increasing
irradiation dose. To interpret these observations, an effective matching field
was defined. Moreover, introducing columnar defects also changes the pinning
force fp qualitatively. Due to stronger pinning of flux lines by the amorphous
defects, the superconducting critical parameters largely exceed those
associated with the defect structures in the unirradiated as-grown material:
Jc,irrad(77 K, 5 T) ^3 10* Jc,ref(77 K, 5 T).

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The categories of this paper are: gr-qc
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The categories of this paper are: ao-sci
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex
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The categories of this paper are: q-fin
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The categories of this paper are: dg-ga
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The categories of this paper are: comp-gas
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The categories of this paper are: math-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: physics
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The categories of this paper are: hep-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-ex