Switching functionality in long-range coupled 2D nanostructure arrays
Two-dimensional nanostructure arrays allow precise tailoring of the relevant intra-system interactions and thermodynamic properties via control of the nanostructure arrangement, size and material. Artificially nanostructured systems will be used within this project as model systems for thermodynamic properties on a fully controllable ensemble and to observe exotic quasiparticles such as magnetic quasi-monopoles. In the context of the VI it is important to note that frustration and ordering effects encountered in complex solids due to the interplay between different electronic, magnetic and structural degrees of freedom can be generated in nanostructure arrays and thus studied in a controllable model system. In particular for thermally driven dynamics, X-ray techniques provide the nanometer spatial resolution required for these studies. Coherent illumination as available on the RIXCS endstation at BESSYII will allow a spatially resolved characterization of the dynamics.
We expect the project to lead to fundamental insight in ordering phenomena (spin ice and frustration; magnetic quasi-monopoles and Dirac strings; domain formation), including order at phase transitions. The nanostructures will be generated via the use of the TU Berlin NanoWerkbank. Via the study of magnetic switching processes and their dependence on the design of the energy landscape, the project has relevance for applications in high-density magnetic data storage.
The goal of the project is to investigate the role of local frustration for the emergence of long-range structure.
The project connects to studies of magnetic phase transformations after optical excitation (P9) as well as the formation of domains by locally modulated electronic and structural properties in complex solids (P7, P8), frustration in water/ice (a continuous research topic of the Wernet/Föhlisch group at HZB) and the development of resonant coherent scattering methodology to image such modulations (P5 and Stöhr).