Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Orientational pinning and transverse voltage: Simulations and
  experiments in square Josephson junction arrays   We study the dependence of the transport properties of square Josephson
Junctions arrays with the direction of the applied dc current, both
experimentally and numerically. We present computational simulations of
current-voltage curves at finite temperatures for a single vortex in the array
($Ha^2/\Phi_0=f=1/L^2$), and experimental measurements in $100\times1000$
arrays under a low magnetic field corresponding to $f\approx0.02$. We find that
the transverse voltage vanishes only in the directions of maximum symmetry of
the square lattice: the [10] and [01] direction (parallel bias) and the [11]
direction (diagonal bias). For orientations different than the symmetry
directions, we find a finite transverse voltage which depends strongly on the
angle $\phi$ of the current. We find that vortex motion is pinned in the [10]
direction ($\phi=0$), meaning that the voltage response is insensitive to small
changes in the orientation of the current near $\phi=0$. We call this
phenomenon orientational pinning. This leads to a finite transverse critical
current for a bias at $\phi=0$ and to a transverse voltage for a bias at
$\phi\not=0$. On the other hand, for diagonal bias in the [11] direction the
behavior is highly unstable against small variations of $\phi$, leading to a
rapid change from zero transverse voltage to a large transverse voltage within
a few degrees. This last behavior is in good agreement with our measurements in
arrays with a quasi-diagonal current drive.

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The categories of this paper are: quant-ph
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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: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: econ
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The categories of this paper are: astro-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: physics
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: nlin
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: q-bio