Berlin 2015 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 17: Postersession I

MM 17.34: Poster

Monday, March 16, 2015, 18:00–20:00, Poster E

Electric field gradients at M- and A-sites in 211 MAX-phases using perturbed angular correlation spectroscopy — Daniel Jürgens¹, Michael Uhmacher¹, Ulrich Vetter¹, Matthias Nagl¹, •Hans Hofsäss¹, Jose Mestnik-Filho², and Michael W. Brasoum³ — ¹Georg-August-Universität Göttingen, II. Physikalisches Institut, Göttingen, Germany — ²Instituto de Pesquisas Energeticas e Nucleares, Sao Paulo, Brazil — ³Department of Material Science and Engineering, Drexel University, PA, USA

Local magnetic fields and electric field gradients at the site of probe atoms in solids can be measured with hyperfine interaction techniques and allows the investigation of the local microstructure around M- and A-sites and possible magnetic properties of MAX-phase compounds, which are known for their metallic as well as their ceramic properties. Since most techniques only allow a macroscopic insight, the perturbed angular correlation (PAC) was used to determine the local environment of implanted probe atoms on atomic scale. Radioactive ¹¹¹In and ¹⁸¹Hf ions, both decaying by a γ−γ cascade, were implanted into Zr₂InC and Hf₂InC and the electric field gradients (EFG) at a A-site (in) and M-sites (Hf) were measured after annealing the implantation damage. We report on the different annealing behavior observed for In and Hf probes. We compare the results with density functional theory calculations and give reasons for dissimilar EFGs at A- and M-sites. Further results for other 211 MAX-phases (Ti₂InC, Ti₂AlC, V₂AlC, Cr₂AlC, Nb₂AlC, Ti₂AlN,Cr₂GeC, Ti₂GeC,Nb₂AsC, and Ti₂SiC) are presented.