Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: NMR Evidence of Antiferromagnetic Spin Fluctuations in
  Nd$_{0.85}$Sr$_{0.15}$NiO$_2$   Despite the recent discovery of superconductivity in
Nd$_{1-x}$Sr$_{x}$NiO$_2$ thin films, the absence of superconductivity and
antiferromagnetism in their bulk materials remain a puzzle. Here we report the
$^{1}$H NMR measurements on powdered Nd$_{0.85}$Sr$_{0.15}$NiO$_2$ samples by
taking advantage of the enriched proton concentration after hydrogen annealing.
We find a large full width at half maximum of the spectrum, which keeps
increasing with decreasing the temperature and exhibits an upturn behavior at
low temperatures. The spin-lattice relaxation rate $1/^{1}T_1$ is strongly
enhanced when lowering the temperature, developing a broad peak at about 40 K,
then decreases following a spin-wave-like behavior $1/^{1}T_1{\sim}T^2$ at
lower temperatures. These results evidence a short-range glassy
antiferromagnetic ordering of magnetic moments below 40 K and dominant
antiferromagnetic fluctuations extending to much higher temperatures. Our
findings reveal the strong electron correlations in bulk
Nd$_{0.85}$Sr$_{0.15}$NiO$_2$, and shed light on the mechanism of
superconductivity observed in films of nickelates.

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The categories of this paper are: hep-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: econ
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The categories of this paper are: math-ph
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The categories of this paper are: nlin
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The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg
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The categories of this paper are: astro-ph
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The categories of this paper are: cs
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: q-fin