Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic Guinier law   Small-angle scattering of x-rays and neutrons is a routine method for the
determination of nanoparticle sizes. The so-called Guinier law represents the
low-q approximation for the small-angle scattering curve from an assembly of
particles. The Guinier law has originally been derived for nonmagnetic
particle-matrix-type systems, and it is successfully employed for the
estimation of particle sizes in various scientific domains (e.g., soft matter
physics, biology, colloidal chemistry, materials science). An important
prerequisite for it to apply is the presence of a discontinuous interface
separating particles and matrix. Here, we introduce the Guinier law for the
case of magnetic small-angle neutron scattering (SANS) and experimentally
demonstrate its applicability for the example of nanocrystalline cobalt. It is
well-known that the magnetic microstructure of nanocrystalline ferromagnets is
highly nonuniform on the nanometer length scale and characterized by a spectrum
of continuously varying long-wavelength magnetization fluctuations, i.e., these
systems do not manifest sharp interfaces in their magnetization profile. The
magnetic Guinier radius depends on the applied magnetic field, on the magnetic
interactions (exchange, magnetostatics), and on the magnetic anisotropy-field
radius, which characterizes the size over which the magnetic anisotropy field
is coherently aligned into the same direction. In contrast to the nonmagnetic
conventional Guinier law, the magnetic version can be applied to fully dense
random-anisotropy-type ferromagnets.

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The categories of this paper are: hep-ex
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The categories of this paper are: physics
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The categories of this paper are: cs
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin
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The categories of this paper are: chem-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-bio
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The categories of this paper are: gr-qc
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: eess
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The categories of this paper are: astro-ph