Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Impact of size mismatch induced quenched disorder on phase fluctuation
  and low field magnetotransport in polycrystalline $Nd_{0.58-x} Gd_x Sr_{0.42}
  Mn O_3$   We report the magnetic and electrical transport properties of the bulk
polycrystalline NGSMO (x ~ 0.0, 0.04, 0.08, 0.12, 0.16, 0.20, 0.25, 0.30, 0.35
and 0.42) synthesized by solid state reaction at 1350 degree Celsius. All the
samples are single phase and have grain size ~1-2 micrometer. The variation of
magnetic and magnetotransport properties as a function of the variance sigma^2
show some interesting trends. As sigma^2 increases, the
paramagnetic-ferromagnetic (PM-FM) transition shows a gradual decrease and
broadening, while the decrease in insulator metal transition (IMT) is
accompanied by sharpening. However, near equality of TC and TIM at intermediate
values of sigma2 could be understood in terms of the competing quenched and the
grain boundary disorder. The variation of peak MR (maximum MR around TC/TIM)
with sigma2 shows that maximum low field MR =35 % at H=3 kOe (68 % at H=10 kOe)
is centered around sigma2 = 0.009857 {A}2 (x=0.25). This shows that huge
intrinsic MR can be obtained at relatively higher temperatures and lower
magnetic fields in the region of enhanced phase fluctuations.

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The categories of this paper are: eess
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The categories of this paper are: stat
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The categories of this paper are: math-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: chao-dyn
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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: supr-con
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The categories of this paper are: econ
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: solv-int
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The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-ex
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The categories of this paper are: acc-phys