Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The role of magnetic excitations in magnetoresistance and Hall effect of
  slightly TM-substituted BaFe$_{2}$As$_2$ compounds (TM = Mn, Cu, Ni)   We report on electrical resistivity, magnetoresistance (MR) and Hall effect
measurements in four non-superconducting BaFe$_{2-x}$TM$_x$As$_2$ (TM = Mn, Cu
and Ni) single crystals with small values of the chemical substitution $x$. The
spin density wave (SDW) ordering that occurs in these systems at temperatures
$T\sim$ (120 - 140) K, in close vicinity to a tetragonal/orthorhombic
transition, produces significant modifications in their magneto-transport
properties. While in the magnetically ordered phase the MR is positive and its
magnitude increases with decreasing temperatures, in the paramagnetic regime
the MR becomes vanishingly small. Above the spin density wave transition
temperature ($T_{\text{SDW}}$) the Hall coefficient $R_H$ is negative, small
and weakly temperature dependent, but a remarkable change of slope occurs in
the $R_H$ versus $T$ curves at $T = T_{\text{SDW}}$. The Hall coefficient
amplitude, while remaining negative, increases steadily and significantly as
the temperature is decreased below $T_{\text{SDW}}$ and down to $T =$ 20 K. The
qualitative behavior of both MR and Hall coefficient is weakly dependent on the
chemical substitution in the studied limit. The experiments provide strong
evidence that scattering of charge carriers by magnetic excitations has to be
taken into account to explain the behavior of the resistivity,
magnetoresistance and Hall effect in the ordered phase of the studied
compounds. Effects of multiple band conduction also must be considered for a
complete interpretation of the results.

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The categories of this paper are: math
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
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The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con