Modern magnetic materials

Even the best measurement can only be as good as the samples it's working with.

Crystal structure of YIG

Therefore, the fabrication of samples tailored to the exact needs of the individual measurements is an important part of our research.

We use sputter deposition to fabricate magnetic or metallic thin films. In particularly, we focus on the fabrication of magnetic iron garnets, that are one of the best material systems for magnetotransport and spin dynamics. Iron garnets are insulators, which allows to separate spin and charge currents, and feature exceptional magnetic properties, such as a low ferromagnetic resonance linewidth and a long magnon propagation length. We used one of the representatives of this material class, yttrium iron garnet (Y3Fe5O12, YIG) to study which parameters govern their crystallization. This knowledge now enables us to fabricate non-planar structures, such as steps. We also fabricate magnetic metal thin films for magnetotransport experiments as well as metallic heterostructures, where controlling the layers allows to tune the magnetic anisotropy from an in-plane alignment to a perpendicular magnetic anisoptropy (PMA). Finally, we fabricate thin films of materials featuring a high spin orbit coupling for the spin to charge conversion in magnetotransport experiments.

Sailler et al. Physical Review Materials 8, 043402 (2024).
DOI: 10.1103/PhysRevMaterials.8.043402

Sailler et al., Physical Review Materials 8, L020402 (2024).
DOI: 10.1103/PhysRevMaterials.8.L020402

EBSD data of polycrystalline YIG on SiOx

To optimize the samples, we characterize their structural and magnetic properties. For the structural characterization we use techniques such as X-ray diffraction, electron and optical microscopy, electron backscatter diffraction and atomic force microscopy, whereas for the magnetic characterization we use for example SQUID magnetometry, ferromagnetic resonance experiments and magnetooptical Kerr microscopy. Within the physics department, many of the devices for characterization are shared between different groups, which offers a wide range of possibilities.

SEM picture of a three terminal nanostructure

Together with the fabrication of the thin films and heterostructures themselves, we also develop our own nanostructures and devices, using the equipment offered within the nano.lab core facility.