Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Low power continuous-wave all-optical magnetic switching in
  ferromagnetic nanoarrays   All-optical magnetic switching promises ultrafast, high-resolution
magnetisation control with the technological attraction of requiring no
magnetic field. Existing all-optical switching schemes are driven by ultrafast
transient effects, typically requiring power-hungry femtosecond-pulsed lasers
and complex magnetic materials. Here, we demonstrate deterministic, all-optical
magnetic switching in simple ferromagnetic nanomagnets (Ni$_{81}$Fe$_{19}$,
Ni$_{50}$Fe$_{50}$) with sub-diffraction limit dimensions using a focused
low-power, linearly-polarised continuous-wave laser. Isolated nanomagnets are
switched across a range of dimensions, laser wavelengths and powers. All
square-geometry artificial spin ice vertex configurations are written,
including ground-state and energetically-unfavourable `monopole-like' states at
powers as low as 2.74 mW. Usually, magnetic switching with linearly polarised
light is symmetry-forbidden; however, here the laser spot has a similar size to
the nanomagnets, producing an absorption distribution dependent on the relative
nanoisland-spot displacement. We attribute the observed deterministic switching
to the transient dynamics of this asymmetric absorption. No switching is
observed in Co samples, suggesting the multi-species nature of NiFe alloys
plays a role in reversal. The results presented here usher in cheap, low-power
optically-controlled devices with impact across data storage, neuromorphic
computation and reconfigurable magnonics.

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The categories of this paper are: physics
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
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The categories of this paper are: q-bio
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
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The categories of this paper are: math