Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 26: Focus: Towards quantitative magnetic measurements at ultimate spatial resolution with electrons

MA 26.3: Hauptvortrag

Mittwoch, 18. März 2015, 10:45–11:15, EB 202

Visualization Of Three Dimensional Magnetization Of Magnetic Nanostructures — •Charudatta Phatak — Argonne National Laboratory, Chicago, USA

Confinement of magnetic structures geometrically as well as energetically leads to novel and unexpected behavior. With advances in fabrication and lithography tools, magnetic structures can be made in complex, confined three-dimensional (3D) geometries at the nanoscale as well as patterned into a variety of interacting lattices. In order to control their behavior, it is necessary to understand the fundamental physics of such interactions along with the influence of physical shape of the nanostructures in 3D.

Lorentz transmission electron microscopy (LTEM) has been extensively used for characterizing magnetization and domains in magnetic structures as it offers a high spatial resolution along with direct visualization of the magnetization. LTEM combined with phase retrieval can be used to obtain quantitative information about the magnetization and interactions between nanostructures. In this work, we will present results using a dedicated Lorentz microscope equipped with a spherical aberration corrector which offers a highest spatial resolution of 0.5 nm while maintaining the sample in a field free region. In this work, we will present a brief introduction to the vector field tomography technique for 3D visualization of magnetization and demonstrate its application to various magnetic systems such as artificial spin ice lattices, shape memory alloys, and magnetic nanowires.