Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct imaging of the coexistence of ferromagnetism and
  superconductivity at the LaAlO3/SrTiO3 interface   LaAlO3 and SrTiO3 are insulating, nonmagnetic oxides, yet the interface
between them exhibits a two-dimensional electron system with high electron
mobility,1 superconductivity at low temperatures,2-6 and electric-field-tuned
metal-insulator and superconductorinsulator phase transitions.3,6-8 Bulk
magnetization and magnetoresistance measurements also suggest some form of
magnetism depending on preparation conditions5,9-11 and suggest a tendency
towards nanoscale electronic phase separation.10 Here we use local imaging of
the magnetization and magnetic susceptibility to directly observe a landscape
of ferromagnetism, paramagnetism, and superconductivity. We find submicron
patches of ferromagnetism in a uniform background of paramagnetism, with a
nonuniform, weak diamagnetic superconducting susceptibility at low temperature.
These results demonstrate the existence of nanoscale phase separation as
suggested by theoretical predictions based on nearly degenerate interface
sub-bands associated with the Ti orbitals.12,13 The magnitude and temperature
dependence of the paramagnetic response suggests that the vast majority of the
electrons at the interface are localized, and do not contribute to transport
measurements.3,6,7 In addition to the implications for magnetism, the existence
of a 2D superconductor at an interface with highly broken inversion symmetry
and a ferromagnetic landscape in the background suggests the potential for
exotic superconducting phenomena.

32
The categories of this paper are: atom-ph
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys