In the majority of cases nanostructures prepared by focused electron beam induced deposition (FEBID) employing an organometallic precursor contain predominantly carbon-based ligand dissociation products. This is unfortunate with regard to using this high-resolution direct-write approach for the preparation of nanostructures for various fields, such as mesoscopic physics, micromagnetism, electronic correlations, spin-dependent transport and numerous applications. Here we present an in-situ cleaning approach to obtain pure Co-FEBID nanostructures. The purification procedure lies in the exposure of heated samples to a H2 atmosphere in conjunction with the irradiation by low-energy electrons. The key finding is that the combination of annealing at 300∘C, H2 exposure and electron irradiation leads to compact, carbon- and oxygen free Co layers down to a thickness of about 20\,nm starting from as-deposited Co-FEBID structures. In addition to this, in temperature-dependent electrical resistance measurements on post-processed samples we find a typical metallic behavior. In low-temperature magneto-resistance and Hall effect measurements we observe ferromagnetic behavior.
@article{arxiv.1504.01945,
title = {Post-growth purification of Co nanostructures prepared by focused electron beam induced deposition},
author = {Evgeniya Begun and Oleksandr V. Dobrovolskiy and Maksym Kompaniiets and Roland Sachser and Christian Gspan and Harald Plank and Michael Huth},
journal= {arXiv preprint arXiv:1504.01945},
year = {2017}
}