Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fish-tail Effect and Irreversibility Field of
  (Cu,C)Ba$_{2}$Ca$_{3}$Cu$_{4}$O$_{x}$-(LiF)$_{y}$ superconductor   Addition of (LiF)$_{y<0.15}$, and of proper amount of (AgO)$_{z=0.45-0.8}$ as
oxidizing agent, to (Cu,C)Ba$_{2}$Ca$_{3}$Cu$_{4}$O$_{10+d}$ superconductor is
useful to control and shift the doping characteristics (hole density and
distribution, and level of disorder) into the region where the irreversible
properties, i.e. fish-tail effect (FTE) and irreversibility field H$_{irr}$,
are improved. Among notable effects are the development of the second
magnetization peak with a higher amplitude J$_{c}$, max and the enhancement of
H$_{irr}$ at high temperatures, above a certain value T* which depends on both
y$_{LiF}$ and z$_{AgO}$. The best results are obtained for the sample with
y$_{LiF}$=0.1 and z$_{AgO}$=0.73. This sample preserves its single phase
Cu,C-1234 composition. The influence on the FTE and H$_{irr}$ of the interplay
between doping characteristics, controlled by LiF and AgO content, is
discussed.

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The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: math-ph
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The categories of this paper are: physics
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The categories of this paper are: eess
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: astro-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: acc-phys
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The categories of this paper are: econ
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ph