The aim of this proposal is to investigate magnetic frustration in different materials. In particular, we are investigating the main magnetic interactions responsible for ordering in quasi crystals and the related periodic approximant lattices. Using Monte Carlo and mean-field techniques we deduce what type of magnetic correlations are present at sub-kelvin temperatures. Numerically we calculate thermodynamic quantities that we compare directly with experiments.
The project is a collaboration between a large group of theorists and experimentalists and we have conducted multiple experiments, including susceptibility, heat capacity and neutron scattering measurements on magnetic quasicrystals and approximants.
Daniel Qvarngård is working as a PhD student within the KAW funded project on magnetic quasicrystals. During the past year Daniel prepared and ported the code needed for calculations of quasicrystal properties, and we are now ready for large-scale simulations to compare results with our experimental colleagues.
It is essential to our theoretical work to be able to perform large scale computations. Since changes in thermodynamic variables are often subtle, we need to be able to perform calculations at high accuracy, which demands large scale computations. What unites all systems is the presence of a strong dipolar interaction. The ill-conditioned
long-ranged intrinsically frustrated dipolar interaction is the main reason for the use of
Dardel: significant computational resources are necessary in order to extract the pertinent behavior, and we have designed software that runs specifically on Dardel and efficiently perform Ewald summations, demagnetization transformations and calculates neutronscattering cross sections for such systems.
A medium allocation on Dardel would allow us to calculate thermodynamic quantities and neutron scattering spectra, needed for comparison with experiment. This project is also related to neutron scattering which is the main purpose of the 1 800 M€ European Spallation Source (ESS) under construction in Lund, and therefore of strategic importance to Sweden.