Dresden 2017 – wissenschaftliches Programm
MA 37.3: Vortrag
Mittwoch, 22. März 2017, 10:00–10:15, HSZ 401
Magnetic nanoparticles as building blocks for hierachically designed samples to investigate collective magnetic phenomena — •Alexander Fabian1, Matthias T. Elm1,2, Detlev M. Hofmann1, and Peter J. Klar1 — 1I. Physikalisches Institut, Heinrich-Buff-Ring 16, 35392 Giessen — 2Physikalisch-Chemisches Institut, Heinrich-Buff-Ring 17, 35392 Giessen
Almost all magnetic phenomena are based on collective interaction of the electrons of the material. The magnetic characteristics of a material such as its hysteresis behavior, is determined by the macroscopic shape of the ferromagnet or the formation of domains. To deepen the understanding of magnetic interactions on different length scales we use nanoparticles as larger building blocks than atoms, which are ordered in hierachically assemblies. Besides from a fundamental view this is interesting for applications, e. g. in high density storage media and spin tronic devices. We describe how spherical magnetite nanoparticles with a diamater of d=20 nm can be assembled in hierachical structures. For this purpose we use a top-down lithographic method combined with the meniscus force deposition method. Characterization is done by angle-dependent ferromagnetic resonance measurements. The results show that on the chosen length scales only the shape of the nanoparticle assemblies determine the magnetic behavior. Moreover the experimental results are accompanied by a theoretical model based on the Smit-Suhl formalism and by micromagnetic calculations to characterize the possible formation of domains in the assemblies.