Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Relevance of ferromagnetic correlations for the Electron Spin Resonance
  in Kondo lattice systems   Electron Spin Resonance (ESR) measurements of the ferromagnetic Kondo lattice
system CeRuPO show a well defined ESR signal which is related to the magnetic
properties of the Ce3+ moment. In contrast, no ESR signal could be observed in
the antiferromagnetic homologue CeOsPO. Additionally, we detect an ESR signal
in a further ferromagnetic Yb compound, YbRh, while it was absent in a number
of Ce or Yb intermetallic compounds with dominant antiferromagnetic exchange,
independently of the presence of a strong Kondo interaction or the proximity to
a (quantum) critical point. Thus, the observation of an ESR signal in a Kondo
lattice is neither specific to Yb nor to the proximity of a quantum critical
point, but seems to be connected to the presence of ferromagnetic fluctuations.
These conclusions not only provide a basic concept to understand the ESR in
Kondo lattice systems even well below the Kondo temperature as observed in the
heavy fermion metal YbRh2Si2 but point out ESR as a prime method to investigate
directly the spin dynamics of the Kondo ion.

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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: nucl-th
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The categories of this paper are: quant-ph
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The categories of this paper are: nlin
3
The categories of this paper are: physics
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The categories of this paper are: gr-qc
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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: acc-phys
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: math-ph
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The categories of this paper are: chem-ph
2
The categories of this paper are: math