Dresden 2020 – scientific programme
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MA: Fachverband Magnetismus
MA 57: Posters Magnetism II
MA 57.55: Poster
Thursday, March 19, 2020, 15:00–18:00, P3
Study of nanoparticle dynamics in binary solutions across phase transitions — •Juri Kopp1, Joachim Landers1, Samira Webers1, Soma Salamon1, Julian Seifert2, Karin Koch2, Annette M. Schmidt2, and Heiko Wende1 — 1Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen — 2Institute for Physical Chemistry, University of Cologne
In previous magnetorheological measurements of cobalt ferrite nanoparticles in aqueous polymer solutions, Webers et al. [1] studied the thermomagnetic behavior across phase transitions showing a distinct change in magnetization. To prepare pre-aligned hybrid materials, it is important to know their stability and magnetic behavior under the influence of phase transitions such as crystallization. Here, we study the dynamics of hematite nanospindles and cobalt ferrite nanoparticles in sucrose solutions of different concentration via temperature dependent Mössbauer spectroscopy and AC-susceptometry (ACS). These methods enable us to analyze the particle mobility and particle orientation across phase transitions. ACS data obtained upon decreasing temperature reveal a supercooled state and spontaneous crystallization whereas during the heating process a mixed-fluid phase is observed, which has also been shown in the Mössbauer spectroscopy results of the sample with the smallest amount of sucrose. This work is supported by the DFG, priority programme SPP1681 (WE 2623/7-3).
[1] S. Webers et al., submitted to ACS Appl. Polym. Mat. (Jul. 2019)