Atomic Diffusion in Solids - Experiments with Neutron Reflectometry
Harald Schmidt
Technische Universität Clausthal, Robert-Koch-Str. 42, 38678 Clausthal-Zellerfeld, Germany E-mail: harald.schmidt@tu-clausthal.de
Self-diffusion of atoms in solids is a fundamental point-defect mediated matter transport process. It plays a key role for the design and optimization of materials as well as for the performance of devices in various branches of technology like energy storage, electronic devices, sensor technology and nanostructural materials design.
The investigation of diffusion processes on very short lengths scales ranging from atomic distances up to some tens of nanometers is an emerging field of research. It is especially important for the characterization of nanostructured materials, metastable compounds and thin films as well as for the study of diffusion process close to room temperature.
During the talk, experiments are presented which are based neutron reflectometry applied to isotope multilayers [1,2]. This method detects the destruction of an artificial lattice of stable isotopes by thermally induced interdiffusion and enables to measure diffusion length down to some Angstroms.
Examples of recent research activities are presented for various classes of materials: Li ion conductors [5], elemental semiconductors [3] and nano-crystalline metallic films [4]. The advantages and further development of the method is discussed.
References
[1] H. Schmidt et al., Phys. Rev. Lett. 96 (2006) 055901.
[2] H. Schmidt et al., Acta Mater. 56 (2008), 464.
[3] E. Hüger et al., Appl. Phys. Lett. 93 (2008) 162104 [4] S. Chakravarty et al., Acta Mater. 59 (2011), 5568.
[5] E. Hüger et al. Phys. Rev. B 85 (2012), 214102.
