Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic and Dielectric Properties of Multiferroic BiFeO3 Nanoparticles
  Synthesized by a Novel Citrate Combustion Method   Single phase BiFeO3 nanoparticles have been successfully synthesized for the
first time by a novel citrate combustion method without using any solvent. Well
mixed metal nitrates along with citric acid which is used as fuel combust to
give BiFeO3 nanoparticles after annealing. These particles are single phase in
nature and crystallize in the rhombohedral distorted perovskite structure
(space group-R3c) which has been confirmed by the Rietveld refinement of the
room temperature powder x-ray diffraction data. Nearly spherical particles of
average particle size 47 nm have been seen from transmission electron
micrograph. Room temperature magnetic hysteresis measurement shows weak
ferromagnetism though the magnetization does not saturate upto 1.75 T applied
field. The coercive field value is calculated to be 180 Oe which is 3 times
higher than that prepared by solvent free combustion method using Glycine. 57Fe
M\"ossbauer spectrum can be fitted with a sextet corresponding to single
magnetic state of hyperfine field about 49.5 T corresponding to Fe3+ state of
the iron atom. The dielectric relaxation and ac conductivity as a function of
frequency have been discussed. High dielectric permittivity has not been found
in these nanoparticles like other reported BiFeO3 ceramics.

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The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: atom-ph
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The categories of this paper are: math-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: econ