Functional materials are the bedrock of modern society. These are materials where the properties, such as magnetic and electric fields, can be changed with external stimuli. This is essential for all devices within information and communication technology, like smartphones and computers. To improve the computing power and energy efficiency it is necessary to develop new types of materials with beneficial magnetic and electronic properties. These new types of materials consist of very small structures, all the way down to nanometer length scales. This miniaturization is very important, as it leads to new magnetic and electric properties.
When trying to make these new materials, through studying the very small structures, it is necessary to see both the properties and the material structure. Optical light microscopes can not see these structures, as they're too small. Thus, we need to use a more advanced form of microscope: the transmission electron microscope (TEM). Instead of using light, it uses electrons for imaging. TEM is commonly used to study the atomic structure of materials, but even if electrons are well-suited to image magnetic and electric fields, the TEM is rarely used to study these.
The goal of this project is to make the TEM more suited to study magnetic and electric fields in materials, by solving two problems hampering the potential of the technique. Firstly, we'll make it easier to see the magnetic and electric fields in materials by implementing better data processing techniques. Secondly, we'll create a 'nanolab-on-a-chip' making it possible to apply an external stimuli to the material. For example by cooling or heating the sample, and seeing how the magnetic properties change. This work will result in new ways of studying nanomaterials with functional properties, making it easier to create new types of materials for use in future devices.
Functional properties in materials, such as magnetic and electric fields, are the bedrock of modern society. They power essential devices in information and communication technologies. With the increasing need for more energy efficient devices, there is a clear demand for prototype device concepts made from novel materials. Since the interesting physics of functional materials often arise at the nanoscale, there is a need for techniques which can study these properties at the lowest length scales.
Scanning transmission electron microscopy (STEM) is a well-established technique for studying the structure and composition of materials, while the ability to study the functional properties of materials have proven to be more problematic. With the advent of a new class of fast pixelated direct electron detectors, it is possible to image functional properties such as nanoscale magnetic and electric fields directly using STEM - differential phase contrast.
This Young talent proposal by Magnus Nord will utilize recent advances in STEM detectors and data processing to establish nanoscale magnetic field mapping within the NORTEM national infrastructure. The project will develop techniques to combine structural and compositional information with direct imaging of functional properties, all at the nanoscale, to study functional materials.
This project aims to: i) develop improved experimental methodologies to image fields relevant for device functionality across different material types, ii) create requisite advanced big data processing open source software, and iii) make in-situ hardware tools for calibrating the microscope for magnetic measurements, and cooling and heating the sample across phase transitions. This will bring Norway and the NORTEM infrastructure in the international forefront of measurements of magnetic fields at the nanoscale in functional materials, linking directly to both fundamental and applied research at Center of Excellence QuSpin and the center FACET.