Homogeneous and Heterogeneous Mechanochemical Reactions in Spinels Studied by Mössbauer Spectroscopy and NMR

• Applicants: Professor Dr. Klaus Dieter Becker; Professor Dr. Paul Heitjans
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2005 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 14433579

Due to their capabilities to probe the local environment of a particular nucleus, solid-state nuclear magnetic resonance and Mössbauer spectroscopy will provide detailed insight into the far-from-equilibrium mechanochemical processes in spinel oxides. Quantitative information on the local structural disorder (a nonequilibrium cation distribution, a canted spin arrangement, an alteration of the nearest-neighbor configuration, a deformation of the polyhedron geometry, etc.) as well as on the diffusion phenomena and dynamics of ions in nanocrystalline complex oxides prepared by mechanochemical routes will be obtained. It will be of major importance to clarify the microscopic mechanism leading to the formation of the core–shell configuration in mechanosynthesized nanoparticles and to expand the understanding of both nonequilibrium ionic distribution and canted spin arrangement within the particle core and shell in the series of related nanostructures of various chemical compositions. Information on the short-range structure, provided by the nuclear spectroscopic techniques, will be complemented by the investigation of the behavior and properties of mechanochemically prepared oxides on a macroscopic scale with the aim to establish the interplay of their nanostructure and magnetism.

• DFG Programme: Research Grants
• Participating Person: Dr. Vladimir Sepelák