Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Intrinsic RESET speed limit of valence change memories   During the last decade, valence change memory (VCM) has been extensively
studied due to its promising features, such as a high endurance and fast
switching times. The information is stored in a high resistive state (logcial
'0', HRS) and a low resistive state (logcial '1', LRS). It can also be operated
in two different writing schemes, namely a unipolar switching mode (LRS and HRS
are written at the same voltage polarity) and a bipolar switching mode (LRS and
HRS are written at opposite voltage polarities). VCM, however, still suffers
from a large variability during writing operations and also faults occur, which
are not yet fully understood and, therefore, require a better understanding of
the underlying fault mechanisms. In this study, a new intrinsic failure
mechanism is identified, which prohibits RESET times (transition from LRS to
HRS) faster than 400 ps and possibly also limits the endurance. We demonstrate
this RESET speed limitation by measuring the RESET kinetics of two valence
change memory devices (namely Pt/TaO$_\mathrm{x}$/Ta and
Pt/ZrO$_\mathrm{x}$/Ta) in the time regime from 50 ns to 50 ps, corresponding
to the fastest writing time reported for VCM. Faster RESET times were achieved
by increasing the applied pulse voltage. Above a voltage threshold it was,
however, no longer possible to reset both types of devices. Instead a unipolar
SET (transition from HRS to LRS) event occurred, preventing faster RESET times.
The occurrence of the unipolar SET is attributed to an oxygen exchange at the
interface to the Pt~electrode, which can be suppressed by introducing an oxygen
blocking layer at this interface, which also allowed for 50 ps fast RESET
times.

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The categories of this paper are: nlin
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The categories of this paper are: alg-geom
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The categories of this paper are: astro-ph
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: cs
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The categories of this paper are: q-bio
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The categories of this paper are: atom-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: econ
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The categories of this paper are: ao-sci
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
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The categories of this paper are: chem-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-alg