| Shrnutí: | Magnetic exchange springs (ESs) are composed of exchange-coupled hard and soft magnetic layers,
i.e., layers with high and low anisotropy, respectively. The moments in the soft layer can be wound up by
applying an external field, which has to be smaller than the anisotropy field of the hard layer. Alternatively,
an ES can be realized by biasing the soft magnetic layer by two adjacent hard magnetic layers with different
magnetic anisotropy directions. We have fabricated an ES layer stack by magnetron sputter deposition.
As the hard magnetic bottom layer, we used epitaxial FePt L10, and as the top layer Co with both layers
having different in-plane easy axes. These hard layers pin the moments of a soft permalloy (Ni81Fe19) layer
sandwiched between them, winding up an ES at remanence. The anisotropy of the polycrystalline top Co
layer was engineered by glancing-angle deposition to have in-plane easy axis anisotropy perpendicular to
the easy direction of the bottom layer. Using soft x-ray spectroscopy and magneto-optical measurements,
we found the in-plane ES to extend from the soft layer into the top layer of our FePt/permalloy/Co trilayer
structure.
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