Berlin 2015 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 17: Postersession I

MM 17.33: Poster

Montag, 16. März 2015, 18:00–20:00, Poster E

Investigations of electric field gradients at A-sites in the 312- and 413-MAX-phases using perturbed angular correlation spectroscopy — Daniel Jürgens¹, Michael Uhrmacher¹, •Hans Hofsäss¹, and Michael W. Barsoum² — ¹Georg-August-Universität Göttingen, II. Physikalisches Institut, Göttingen, Germany — ²Department 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. The perturbed angular correlation (PAC) was used to determine the local environment of implanted probe atoms on atomic scale. The compounds Ti₃AlC₂, Ti₃SiC₂, Ti₄AlN₃ and Ta₄AlC₃ were investigated with PAC using implanted 111In probe atoms., which occupy A-sites after annealing the implantation damage. In this study we investigate dependence of the strength of the electric field gradient (EFG) on the stacking sequence of the laminar MAX phases. The comparison of EFGs measured in the different sub-groups of MAX phases show that the EFGs in the 413 phases are slightly smaller compared to the corresponding 211 phase. Increasing the M-X intermediate layer thickness while going from M₂X to M₃X₂ to M₄X₃ phases reduces the EFG strength at the A-Site. This behavior allows a characterization of stacking sequence variations occurring e.g. in thin film MAX phases.