Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Manipulation of the spin helix in FeGe thin films and FeGe/Fe
  multilayers   Magnetic materials without structural inversion symmetry can display the
Dzyaloshinskii-Moriya interaction, which manifests itself as chiral magnetic
ground states. These chiral states can interact in complex ways with applied
fields and boundary conditions provided by finite sample sizes that are of the
order of the lengthscale of the chiral states. Here we study epitaxial thin
films of FeGe with a thickness close to the helix pitch of the helimagnetic
ground state, which is about 70 nm, by conventional magnetometry and polarized
neutron reflectometry. We show that the helix in an FeGe film reverses under
the application of a field by deforming into a helicoidal form, with twists in
the helicoid being forced out of the film surfaces on the way to saturation. An
additional boundary condition was imposed by exchange coupling a ferromagnetic
Fe layer to one of the interfaces of an FeGe layer. This forces the FeGe spins
at the interface to point in the same direction as the Fe, preventing node
expulsion and giving a handle by which the reversal of the helical magnet may
be controlled.

2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat