Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spatially controlled formation of superparamagnetic (Mn,Ga)As
  nanocrystals in high temperature annealed (Ga,Mn)As/GaAs superlattices   The annealing-induced formation of (Mn,Ga)As nanocrystals in (Ga,Mn)As/GaAs
superlattices was studied by X-ray diffraction, transmission electron
microscopy and magnetometry. The superlattice structures with 50 A thick
(Ga,Mn)As layers separated by 25, 50 and 100 A thick GaAs spacers were grown by
molecular beam epitaxy at low temperature (250 C), and then annealed at high
temperatures of: 400, 560 and 630 C. The high temperature annealing causes
decomposition to GaMnAs ternary alloy and formation of (Mn,Ga)As nanocrystals
inside the GaAs matrix. The nanocrystals are confined in the planes that were
formerly occupied by (Ga,Mn)As layers for up to the 560 C of annealing and
diffuse throughout the GaAs spacer layers at 630 C annealing. The corresponding
magnetization measurements show the evolution of the magnetic properties of
as-grown and annealed samples from ferromagnetic, through superparamagnetic to
the combination of both.

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The categories of this paper are: bayes-an
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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
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The categories of this paper are: math-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: eess
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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: cs
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The categories of this paper are: chao-dyn
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The categories of this paper are: stat
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The categories of this paper are: patt-sol
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The categories of this paper are: chem-ph