Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct measurement of charge transfer phenomena at
  ferromagnetic/superconducting oxide interfaces   YBa2Cu3O7-x/La0.67Ca0.33MnO3 ferromagnetic/superconducting interfaces are
analyzed by scanning transmission electron microscopy and electron energy loss
spectroscopy with monolayer resolution. We demonstrate that extensive charge
transfer occurs between the manganite and the superconductor, in a manner
similar to modulation-doped semiconductors, which explains the reduced critical
temperatures of heterostructures. This behavior is not seen with insulating
PrBa2Cu3O7 layers. Furthermore, we confirm directly that holes in the
YBa2Cu3O7-x are located on the CuO2 planes.

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The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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The categories of this paper are: quant-ph
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int