Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ferromagnetic resonance of a two-dimensional array of nanomagnets:
  Effects of surface anisotropy and dipolar interactions   We develop an analytical approach for studying the FMR frequency shift due to
dipolar interactions and surface effects in two-dimensional arrays of
nanomagnets with (effective) uniaxial anisotropy along the magnetic field. For
this we build a general formalism on the basis of perturbation theory that
applies to dilute assemblies but which goes beyond the point-dipole
approximation as it takes account of the size and shape of the nano-elements,
in addition to their separation and spatial arrangement. The contribution to
the frequency shift due to the shape and size of the nano-elements has been
obtained in terms of their aspect ratio, their separation and the lattice
geometry. We have also varied the size of the array itself and compared the
results with a semi-analytical model and reached an agreement that improves as
the size of the array increases. We find that the red-shift of the
ferromagnetic resonance due to dipolar interactions decreases for smaller
arrays. Surface effects may induce either a blue-shift or a red-shift of the
FMR frequency, depending on the crystal and magnetic properties of the
nano-elements themselves. In particular, some configurations of the
nano-elements assemblies may lead to a full compensation between surface
effects and dipole interactions.

11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph