Research - old
Research activities led by Michal Urbánek
Magnonics
T. Hache et al., Free-standing and positionable microwave antenna device for magneto-optical spectroscopy experiments, arXiv:1911.11517.
L. Flajšman et al., Zero-field propagation of spin waves in waveguides prepared by focused ion beam direct writing, Accepted in PRB 18 Dec 2019, arXiv:1906.12254.
3D magnetic nanostructures by FEBID/FIBID
Coming soon...
Magnetic patterning by focused ion beam writing
Direct writing of magnetic patterns by focused-ion-beam irradiation presents a favorable alternative to the conventional lithography approaches. We study epitaxially grown metastable face-centered cubic (fcc) Fe thin films which undergo structural (fcc->bcc) and magnetic (paramagnetic->ferromagnetic) phase transformation upon ion-beam-irradiation. By using focused ion beam we were able to write ferromagnetic (bcc Fe) patterns into the paramagnetic (fcc Fe) layer with sub-100 nm resolution with control over the saturation magnetization (irradiation dose) and even anisotropy (irradiation scanning direction). The patterned regions could be used as a magnonic waive-guides (see section Magnonics).
For further details, contact Michal Urbánek (michal.urbanek(at)ceitec.vutbr.cz).
Related publications:
- J. Gloss et al., Applied Surface Science 469, 747-752 (2019). DOI: 10.1016/j.apsusc.2018.10.263. arXiv:1807.08055.
- Urbánek et al., APL Materials 6, 060701 (2018). DOI: 10.1063/1.5029367
- Gloss et. al., Applied Physics Letters 103, 262405 (2013). DOI: 10.1063/1.4856775.
Magnetic vortices
Magnetic vortices are curling magnetization structures formed in micro- and nanosized magnetic disks and polygons. They are known for having four different magnetization configurations (vortex states) that can be used for a multibit memory cell. We study dynamic magnetization processes of switching of the vortex states and we investigate the possibilities of writing two bits of information into a magnetic vortex. While most of the work has been done on planar structures, more recently we have been studying 3D vortices in micro- and nanosized spheres.
For further details, contact Michal Urbánek (michal.urbanek(at)ceitec.vutbr.cz).
Related publications:
- Vaňatka et al., AIP Advances 7 (10), 105103 (2017). DOI: 10.1063/1.5006235.
- Uhlíř et. al., Nature Nanotechnology 8, 341–346 (2013). DOI: 10.1038/nnano.2013.66.
Metamagnetic nanostructures
Emergent behavior in nanostructures featuring first-order phase transition from the antiferromagnetic to ferromagnetic state.
In case of FeRh the magnetic ordering is related to change in structure and other properties such as resistivity.
