Regensburg 2022 – scientific programme

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MA: Fachverband Magnetismus

MA 41: Micro- and Nanostructured Magnetic Materials

MA 41.2: Talk

Friday, September 9, 2022, 11:45–12:00, H47

Quantitative analysis of magnetic states in an artificial spin ice by off-axis electron holography — •Teresa Weßels^1,2, Sebastian Gliga³, Simone Finizo³, Andras Kovacs², and Rafal Dunin-Borkowski² — ¹Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University Duisburg-Essen, 47057 Duisburg, Germany — ²Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany — ³Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland

The study of emergent phenomena in artificial spin ices (ASIs) consisting of patterned nanomagnets is presently the focus of intense research. We used off-axis electron holography in the transmission electron microscope to quantitatively measure the magnetic phase shift induced by ASI with chiral geometry. The phase shift of the electron wave was measured using an electron biprism and interpreted using a model-based iterative reconstruction algorithm to retrieve the projected in-plane magnetization. The permalloy nanomagnets were patterned on a SiN membrane using lift-off lithography. Magnetic interactions within individual arrays were studied by applying in-plane magnetic fields to the sample. The reconstructed magnetization shows a single-domain state of the nanomagnets with an average magnetic polarization of 0.73 T. The low magnetic polarization value may result from a combination of the microstructure, composition, and oxidation. The project received funding from the ERC (856538) and the DFG (392476493, 405553726).