Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: ^{75}As NMR study of the growth of paramagnetic-metal domains due to
  electron doping near the superconducting phase in LaFeAsO_{1-x}F_{x}   We studied the electric and magnetic behavior near the phase boundary between
antiferromagnetic (AF) and superconducting (SC) phases for a prototype of
high-T_c pnictides LaFeAsO_{1-x}F_{x} by using nuclear magnetic resonance, and
found that paramagnetic-metal (PM) domains segregate from AF domains. PM
domains grow in size with increasing electron doping level and are accompanied
by the onset of superconductivity, and thus application of pressure or
increasing the doping level causes superconductivity. The existence of PM
domains cannot be explained by the existing paradigm that focuses only on the
relationship between superconductivity and antiferromagnetism. Based on orbital
fluctuation theory, the existence of PM domains is evidence of the
ferroquadrupole state.

30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math