Dresden 2017 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 3: Focus: Ferroics with Mesoscopic Order
DF 3.5: Talk
Monday, March 20, 2017, 11:30–12:00, WIL B321
Multiferroic effects in nanoparticulate systems — •Soma Salamon1, Joachim Landers1, Marianela Escobar2, Muhammad Naveed-Ul-Haq2, Vladimir Shvartsman2, Morad Etier2, Doru C. Lupascu2, and Heiko Wende1 — 1Faculty of Physics and CENIDE, University of Duisburg-Essen — 2Institute for Materials Science and CENIDE, University of Duisburg-Essen
Both intrinsic and composite multiferroic nanoparticles have been investigated using a variety of measurement methods. Representing an intrinsic multiferroic, bismuth ferrite (BiFeO3) nanoparticles were examined by Mössbauer spectroscopy to analyze the size and temperature dependence of the cycloidal spin structure and its anharmonicity. This was done to investigate whether the cycloid can be inhibited by sufficiently small particle diameters, potentially inducing a net magnetic moment in the otherwise antiferromagnetic material. Results indicate that the spin cycloid exists even in particles small compared to the period length of the cycloid (ca. 62 nm). Representing a composite multiferroic, cobalt ferrite-barium titanate (CoFe2O4-BaTiO3) core-shell nanoparticles were synthesized, resulting in a ferroelectric BaTiO3 shell and a ferrimagnetic CoFe2O4 core. This was followed by the preparation of ceramics through sintering techniques, producing magnetostrictive regions in a piezoelectric matrix. The strain coupling between the two constituents was verified by successful measurements of the direct and converse magnetoelectric effect on these samples. This work was supported by the DFG (FOR 1509) and Stiftung Mercator (MERCUR).