Talk (non-conference) (Invited)

FZJ-2025-04466

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Collective phenomena in magnetic nanoparticle systems and complex oxide thin films - and future plans

Petracic, O.FZJ*

2025

Abstract: In recent decades, there has been considerable interest in synthesizing, characterizing, andmodeling magnetic nanoparticles. This interest stems from the wide array of potential oralready existing applications such as functional materials, ferrofluids, smart coatings, novelspintronic devices, magnetic tracers for medical imaging methods, targeted drug delivery,magnetic hyperthermia, magnetic separation, and many more. Here I will discuss variousresults on iron oxide nanoparticles (IONPs) and focus on three aspects: properties of individualIONPs, collective properties of interacting IONPs, and properties coming from the coupling to aferroelectric substrate. In a second part, I will discuss properties of thin films of complex oxides.Complex oxides display multiple phenomena, including various types of magnetism,superconductivity, colossal magnetoresistance, and ferroelectricity. Specifically, the presenceof oxygen vacancies can result in large ionic conductivities. We have investigated epitaxial thinfilms of La0.7Sr0.3MnO3-δ and La0.7Sr0.3CoO3-δ. Gradual release of oxygen causes a topotactic phasetransition from the initial, ferromagnetic metallic perovskite structure to an antiferromagneticinsulating brownmillerite structure. In the third part, I will briefly discuss future plans in thearea of collective phenomena in JCNS-2.

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Contributing Institute(s):

1. Streumethoden (JCNS-2)
2. JARA-FIT (JARA-FIT)

Research Program(s):

1. 632 - Materials – Quantum, Complex and Functional Materials (POF4-632) (POF4-632)
2. 6G4 - Jülich Centre for Neutron Research (JCNS) (FZJ) (POF4-6G4) (POF4-6G4)

Appears in the scientific report 2025

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