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DS: Fachverband Dünne Schichten

DS 8: Thin Film Properties II

DS 8.7: Talk

Wednesday, March 20, 2024, 11:15–11:30, A 060

Defect break-down in systematically disordered Cr₂AlC — •Joao S. Cabaco^{1, 6}, Maciej O. Liedke², Javier Pablo-Navarro^{3, 4}, Fabian Ganss¹, Cesar Magen³, Manuel R. Ibarra^{3, 4}, Ulrich Kentsch¹, Maik Butterling², Andreas Wagner², Jurgen Lindner¹, Jurgen Faßbender^{1, 5}, Christoph Leyens⁶, Richard Boucher⁶, and Rantej Bali¹ — ¹Institute of Ion Beam Physics and Materials Research, HZDR, Germany — ²Institute of Radiation Physics, HZDR, Germany — ³Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Spain — ⁴Laboratory of Advanced Microscopies, University of Zaragoza, Spain — ⁵Institute of Solid State and Materials Physics, TU Dresden, Germany — ⁶Institute of Materials Science, TU Dresden, Germany

The presence of open-volume defects, such as vacancies, can influence the structural, magnetic, and transport properties. This study uses ion irradiation to investigate the evolution of defects in MAX-phase Cr₂AlC. Thin-films of 50 nm and 500 nm were irradiated at increasing fluences, using both inert ions and transition metal ions. Through the combined use of positron annihilation and ab-initio simulations, it was possible to distinguish different types of defects, determine their size and concentration. Large clusters of 9-15 vacancies, originally present in the as-grown films, transform into Al mono-vacancies and Cr-Al di-vacancies upon ion irradiation. Furthermore, an overall reduction in open-volume defect concentration and size due to irradiation was observed. Grant: (DFG) TRANSMAX no. 456078299.

Keywords: MAX phases; Vacancies; Di-vacancies; Positron Annihilation; Doppler broadening