Magnetic spectrum imaging at atomic resolution

Dnr:

SNIC 2016/34-6

Type:

SNAC Large

Principal Investigator:

Jan Rusz

Affiliation:

Uppsala universitet

Start Date:

2017-01-01

End Date:

2018-01-01

Primary Classification:

10304: Den kondenserade materiens fysik

Secondary Classification:

21001: Nanoteknik

Tertiary Classification:

10302: Atom- och molekylfysik och optik

Webpage:

Allocation

Abstract

Rapid developments in nanoengineering calls for characterization methods capable to reach high spatial resolution. In this domain, scanning transmission electron microscope (STEM) provides a broad scale of measurement techniques ranging from Z-contrast or electron energy- loss elemental mapping, differential phase contrast, via local electronic structure studies of single atoms to counting individual atoms in nanoparticles. As a specific case of high-spatial resolution electron energy-loss spectroscopy, an electron magnetic circular dichroism (EMCD) method has been introduced as an analogue to x-ray magnetic circular dichroism, which is a well established quantitative method of measuring spin and orbital magnetic moments in an element-selective manner. This CPU-time allocation we enable us to perform large-scale first-principles simulations of the elastic and inelastic scattering of electrons on magnetic materials. In the experiments the magnetic signal observed so far is typically rather weak and obtaining sufficient signal to noise ratios is an issue. Therefore we aim to computationally optimize the measurement conditions for detection of as strong magnetic signal as possible. Development of new measurement setups, for example utilizing phase distribution in electron beams, are planned. Finally, we will perform simulations to provide interpretation to measurements. The primary outcome of this project will be a progress in development of the atomic resolution EMCD technique, which is expected to have a significant impact in the area of nano-magnetism and all its applications.