Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detection and imaging of the oxygen deficiency in single crystalline
  YBa$_{\text{2}}$Cu$_{\text{3}}$O$_{\text{7}-\delta}$ thin films using a
  positron beam   Single crystalline YBa$_{\text{2}}$Cu$_{\text{3}}$O$_{\text{7}-\delta}$
(YBCO) thin films were grown by pulsed laser deposition (PLD) in order to probe
the oxygen deficiency $\delta$ using a mono-energetic positron beam. The sample
set covered a large range of $\delta$ (0.191<$\delta$<0.791) yielding a
variation of the critical temperature $T_{\text{c}}$ between 25 and 90\,K. We
found a linear correlation between the Doppler broadening of the positron
electron annihilation line and $\delta$ determined by X-ray diffraction (XRD).
Both, the origin of the found correlation and the influence of metallic
vacancies, were examined with the aid of ab-initio calculations that allowed us
(i) to exclude the presence of Y vacancies and (ii) to ensure that positrons
still probe $\delta$ despite the potential presence of Ba or Cu vacancies. In
addition, by scanning with the positron beam the spatial variation of $\delta$
could be analyzed. It was found to fluctuate with a standard deviation of up to
$0.079(5)$ within a single YBCO film.

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The categories of this paper are: chem-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: eess
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
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The categories of this paper are: supr-con
1
The categories of this paper are: cs
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph