Dresden 2020 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 6: Micro- and Nanostructured Materials (joint session MA/TT)

MA 6.5: Vortrag

Montag, 16. März 2020, 10:30–10:45, HSZ 403

Microscopic origin of improved magnetic fluid hyperthermia performance of CFO-Pd heterodimers: Element-specific investigations of structural, electronic, and magnetic characteristics — •S. Fatemeh Shams¹, Detlef Schmitz², Alevtina Smekhova², Eugen Weschke², Kai Chen², Chen Luo², Amir. H. Tavabi³, Sussane Pettinger⁴, Konrad Siemensmeyer², Gil Westmeyer⁴, Rafal E. Dunin-Borkowski³, Florin Radu², and Carolin Schmitz-Antoniak¹ — ¹Peter-Grünberg-Institut (PGI-6), Forschungszentrum Jülich, 52425 Jülich, Germany — ²Helmholtz-Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany — ³Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany — ⁴Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, 85764 Neuherberg, Germany

Cobalt ferrite nanoparticles were synthesized and randomly decorated with approximately 2 wt.% of Pd particles. After careful structural and compositional characterization, X-ray absorption spectroscopy was used to investigate their element-specific magnetic properties. A significant increase in the effective spin and orbital magnetic moments of both the Fe and the Co ions was found upon decoration with Pd, leading to an increase in total magnetic moment per formula unit by 60% for the larger nanoparticles and by 200% for the smaller ones at 300 K. XMCD measurements show that the magnetic field dependence of the Co moment is much steeper at lower magnetic fields, leading to an enhanced maximum heating power in hyperthermia experiments.