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MA: Fachverband Magnetismus

MA 36: Magnetic Particles / Clusters

MA 36.1: Vortrag

Donnerstag, 30. März 2023, 09:30–09:45, HSZ 401

Magnetic properties of metastable single-crystalline cobalt iron oxide nanoflakes investigated by Mössbauer spectroscopy — Soma Salamon¹, Joachim Landers¹, •Anna Rabe^1,2, Franz-Philipp Schmidt³, Thomas Lunkenbein³, Malte Behrens², and Heiko Wende¹ — ¹Faculty of Physics and CENIDE, University of Duisburg-Essen — ²Institute of Inorganic Chemistry, Kiel University — ³Department of Inorganic Chemistry, Fritz Haber Institute of the Max Planck Society

Spinel-type transition metal oxides are of high interest for a variety of applications, including heterogeneous catalysis, energy conversion and magnetic materials with fine-tuned properties. The compound Co₂FeO₄ is of particular interest, but its phase diagram contains a large immiscibility. Using Mössbauer spectra recorded at low temperatures (4.3 K) and high magnetic fields (10 T), we were able to precisely determine the distribution of Fe ions across tetrahedral and octahedral sites. This enabled us to characterize the influence of different calcination temperatures from 400 ^∘C up to 900 ^∘C on the phase composition and miscibility, while also providing valuable insights on the temperature dependent evolution of the spectral hyperfine structure. These findings were successfully correlated with results from magnetometry, showing clear signs of a change in magnetic properties based on different degrees of intermixing, interface area, and phase separation, as also supported by TEM and EDX measurements. Financial support by the German Research Foundation (DFG) via the CRC/TRR 247 (Project-ID 388390466, sub-project B02) is gratefully acknowledged.