Structure-Property Relationships in Hexaferrites – Improving Rare-Earth-Free Magnets

During his PhD studies, Jens Plum Frandsen researched the formation pathways and microstructures of hexaferrite magnets. Magnets are essential components of electric motors and generators, and the uncertain supply of rare-earth elements has increased interest in rare-earth-free alternatives such as hexaferrites. Jens Plum Frandsen utilised the chemistry and morphology of iron oxyhydroxide nanocrystals to form the hexaferrite phase and tailor the microstructure in a single step. Structure-property studies identified opportunities for improvement. In addition, he investigated the formation and microstructure of higher-order hexaferrites, which could pave the way for stronger rare-earth-free magnets.

The new research findings contribute to a more sustainable production protocol for hexaferrite magnets with significant industrial potential and advance the understanding of higher-order hexaferrites as promising materials for next-generation magnets.

The PhD study was completed at the Interdisciplinary Nanoscience Center (iNANO), Faculty of Natural Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Friday, 21 August 2026 at 10:15
Place: Building 1523, room 318, Physics Auditorium, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C
Title of PhD thesis: Hexaferrite Magnets: Microstructures and Formation Pathways
Contact information: Jens Plum Frandsen, e-mail: jensplum@chem.au.dk, tel.: +45 26466751
Members of the assessment committee:
Professor Martin Sahlberg, Department of Chemistry, Ångström Laboratory; Inorganic Chemistry, Uppsala University, Sweden
Senior Scientist Stefano Deledda, IFE - Institute for Energy (IFE), Norway
Professor Torben René Jensen (chair), Department of Chemistry, Aarhus University, Denmark
Main supervisor: Professor Mogens Christensen, Department of Chemistry, Aarhus University, Denmark
Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Natural Sciences/GSNS, Ny Munkegade 120, building 1521, 8000 Aarhus C