CAREER: Deciphering emergent orders in frustrated magnets across multiple length and energy scales.

About This Grant

Non-technical Abstract: Magnetic materials exhibit a wide array of phenomena that depend on the arrangement of and interactions between the constituent microscopic magnetic moments. In some materials, the magnetic moments cannot simultaneously satisfy all constraints imposed by the lattice geometry and the interactions between them. The competing interactions in these so called “frustrated magnets” often lead to the emergence of complex magnetic orders governed by quantum fluctuations. These phases may not exhibit a net magnetic field, but owing to their symmetries can still couple to externally applied ones. This property makes frustrated magnets compelling material candidates for energy efficient computing devices that encode information in magnetic degrees of freedom. In this project, the research team utilizes synchrotron x-ray scattering techniques at National labs to study the magnetic configurations and fluctuations of nanoscale frustrated magnets. These measurements will provide critical knowledge enabling the development of future low-power electronic devices. The educational component focuses on training future quantum material researchers through the development of a new cross-disciplinary quantum materials course at Brown University connecting the fundamental physics of quantum materials to quantum information. Technical Abstract: Frustrated magnetic materials can often realize non-collinear or non-coplanar magnetic configurations and textures that exhibit no uniform macroscopic magnetic field but nevertheless can couple to external electric or magnetic fields. Thus, they hold great promise for future fast and low dissipation spintronic devices. To realize such technologies, it is essential to obtain precise knowledge of the magnetic ordering, domain configurations, and excitations in frustrated magnets that have been prepared as device relevant thin film heterostructures and/or exfoliated nanoflakes. However, measuring the magnetic properties over broad length and energy scales in these nano-scale geometries remains a major challenge. This project is addressing this challenge by utilizing resonant x-ray scattering to study the static and dynamic response functions in model frustrated magnets across angstrom to micron length scales. The research team is using nano-focused resonant elastic x-ray scattering to map the spatial variations of magnetic order parameters over large areas in nanoscale samples and to study chiral domain configurations of frustrated magnets. Magnetic excitations in exfoliated two-dimensional frustrated magnets and thin-film geometries are studied over broad energy scales using resonant inelastic x-ray scattering. The microscopic material parameters that are being quantified through this work are essential to guide theoretical frameworks for predicting physical properties of model quantum magnets and provide essential input towards incorporating their novel functionalities into future antiferromagnetic spintronics. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.