Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Determination of characteristic muon precession and relaxation signals
  in FeAs and FeAs2, possible impurity phases in pnictide superconductors   We report muon-spin relaxation measurements of highly homogeneous samples of
FeAs and FeAs2, both previously found as impurity phases in some samples of
recently synthesized pnictide superconductors. We observe well defined muon
precession in the FeAs sample with two precession frequencies of 38.2(3) and
22.7(9) MHz at 7.5 K, with the majority of the amplitude corresponding to the
lower frequency component. In FeAs2 we confirm previous measurements showing
that no long-ranged magnetic order occurs above 2 K and measure the muon spin
relaxation rate, which increases on cooling. Our results exclude the
possibility that previous muon-spin relaxation measurements of pnictide
superconductors have been measuring the effect of these possible impurities.

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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: econ
10
The categories of this paper are: q-bio
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The categories of this paper are: comp-gas
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The categories of this paper are: stat
1
The categories of this paper are: cs
2
The categories of this paper are: math
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The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg