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J. Gloss, M. Horký, V. Křizáková, L. Flajsman, M. Schmid, M. Urbanek, P. Varga:
"The growth of metastable fcc Fe₇₈Ni₂₂ thin films on H-Si(100) substrates suitable for focused ion beam direct magnetic patterning";
Applied Surface Science, 469 (2019), 747 - 752.

We have studied the growth of metastable face-centered-cubic, non-magnetic Fe78Ni22 thin films on silicon
substrates. These films undergo a magnetic (paramagnetic to ferromagnetic) and structural (fcc to bcc) phase
transformation upon ion beam irradiation and thus can serve as a material for direct writing of magnetic nanostructures
by the focused ion beam. So far, these films were prepared only on single-crystal Cu(1 0 0) substrates.
We show that transformable Fe78Ni22 thin films can also be prepared on a hydrogen-terminated Si(1 0 0)
with a 130-nm-thick Cu(1 0 0) buffer layer. The H-Si(1 0 0) substrates can be prepared by hydrofluoric acid
etching or by annealing at 1200 °C followed by adsorption of atomic hydrogen. The Cu(1 0 0) buffer layer and
Fe78Ni22 fcc metastable thin film were deposited by thermal evaporation in ultra-high vacuum. The films were
consequently transformed in-situ by 4 keV Ar+ ion irradiation and ex-situ by a 30 keV Ga+ focused ion beam, and
their magnetic properties were studied by magneto-optical Kerr effect magnetometry. The substitution of expensive
copper single crystal substrate by standard silicon wafers dramatically expands application possibilities
of metastable paramagnetic thin films for focused-ion-beam direct magnetic patterning.

Magnetic nanostructures Metastable films fcc Fe Cu buffer layer Si(1 0 0)