ACHROMAS · Novel Materials Based on Alkali Chromites and Manganites for the Generation of Magnetic Skyrmions

The planned project explores a new class of frustrated magnets with the potential to host magnetic skyrmions. Skyrmions are nanoscale magnetic states and can be characterized as topologically protected spin vortices. They can be manipulated using low electric currents, thus can act as information bits in a new generation of energy efficient, ultradense memory and logic devices. Until now skyrmions have mainly been found in chiral magnets and at the surfaces of certain materials, but are often limited to a tiny pocket of the applied magnetic field versus temperature phase diagram. Furthermore, the skyrmions themselves in these systems are often of tens of nanometers or more in size, thus too large to be useful as information bits. Recent theoretical works have predicted that much more compact skyrmions might be found in frustrated magnets, and guidelines have been established to identify the most desirable structure features for hosting skyrmions. One group of materials that meet the structural criteria are the alkali chromites and manganites ABO2 (A = Na, K, Rb, Cs; B = Cr, Mn) and their derivatives, which are the focus of the proposed research. A comprehensive physicochemical investigation of the ABO2 family will be carried out, using cutting-edge methods of syntheses and modern analysis techniques for the determination of structure and composition. An investigation of their bulk magnetization and transport properties, combined with a study of their magnetic structures using Lorenz microscopy, neutron and resonant X-ray scattering, will enable magnetic phase diagrams to be mapped out and skyrmion phases to be identified and characterized. This interdisciplinary project involves close relationships between multiple related fields of science, such as solid state and magnetochemistry, theoretical physics and condensed matter physics, material science and nanotechnology.