Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase Competition in the Palmer-Chalker XY Pyrochlore Er$_2$Pt$_2$O$_7$   We report neutron scattering measurements on Er$_2$Pt$_2$O$_7$, a new
addition to the XY family of frustrated pyrochlore magnets. Symmetry analysis
of our elastic scattering data shows that Er$_2$Pt$_2$O$_7$ is the first XY
pyrochlore to order into the $k=0$, $\Gamma_7$ magnetic structure (the
Palmer-Chalker state), at $T_N = 0.38$ K. This contrasts with its sister XY
pyrochlore antiferromagnets Er$_2$Ti$_2$O$_7$ and Er$_2$Ge$_2$O$_7$, both of
which order into $\Gamma_5$ magnetic structures at much higher temperatures,
$T_N=1.2$ K and $1.4$ K, respectively. In this temperature range, the magnetic
heat capacity of Er$_2$Pt$_2$O$_7$ contains a broad anomaly centered at
$T^*=1.5$ K. Our inelastic neutron scattering measurements reveal that this
broad heat capacity anomaly sets the temperature scale for strong short-range
spin fluctuations. Below $T_N = 0.38$ K, Er$_2$Pt$_2$O$_7$ displays a gapped
spin wave spectrum with an intense, flat band of excitations at lower energy
and a weak, diffusive band of excitations at higher energy. The flat band is
well-described by classical spin wave calculations, but these calculations also
predict sharp dispersive branches at higher energy, a striking discrepancy with
the experimental data. This, in concert with the strong suppression of $T_N$,
is attributable to enhanced quantum fluctuations due to phase competition
between the $\Gamma_7$ and $\Gamma_5$ states that border each other within a
classically predicted phase diagram.

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The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: gr-qc
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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: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: cs
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The categories of this paper are: eess
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The categories of this paper are: patt-sol
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The categories of this paper are: math
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The categories of this paper are: physics
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an
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The categories of this paper are: stat