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MA: Fachverband Magnetismus

MA 35: Poster 2

MA 35.67: Poster

Donnerstag, 8. September 2022, 16:00–18:00, P4

Formation, effects and suppression of M-Type hexaferrite in barium titanate-spinell ferrite multiferroic composites — •Daniil Lewin, Sofia Shamsulbahrin, Vladimir V. Shvartsman, and Doru C. Lupascu — Institute for Materials Science and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Germany

The combination of a ferroelectric barium titanate-based perovskite with a magnetic ferrite is a common approach for creating multiferroic composites. In some cases, however, a hexagonal phase, usually identified as barium ferrite (BaFe12O19, BaM), appears during sintering. As a noticeable difference exists in the optimal sintering temperature for both phases, it may become a challenge to create an electrically well insulating ceramic. Confronted with strong formation of BaM at high sintering temperatures (1270 °C), we investigate efficient ways to suppress its formation for combinations of barium titanate with cobalt ferrite or nickel ferrite. We show that by using a reducing atmosphere, the formation of BaM is heavily suppressed, while addition of extra cobalt oxide or nickel oxide during the synthesis can further improve the magnetoelectric coefficient while minimizing the remaining amount of BaM. A clear correlation between the amount of BaM and the polarizability and magnetoelectric coupling of the composites is established.