Dresden 2020 – scientific programme
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MA: Fachverband Magnetismus
MA 62: Disodered Magnetic Materials
MA 62.2: Talk
Friday, March 20, 2020, 09:45–10:00, HSZ 401
Variation of open volume defects during magnetic phase transitions — •Maciej Oskar Liedke1, Maik Butterling1, Jonathan Ehrler1, Benedikt Eggert2, William Griggs3, Shadab Anwar1, Rantej Bali1, Thomas Thomson3, Eric Hirschmann1, Ahmed G. Attallah1, Heiko Wende2, and Andreas Wagner1 — 1Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — 2University of Duisburg-Essen, Duisburg, Germany — 3The University of Manchester, Manchester, United Kingdom
Open volume defects in Fe60Al40 and Fe50Rh50 alloy thin films have been investigated with positron annihilation spectroscopy techniques. The distribution of open-volume defect types in Fe60Al40 thin films, i.e., mono-vacancies, triple defects as well as vacancy clusters has been estimated using positron annihilation lifetime spectroscopy. We show that the temperature driven re-ordering kinetics can be strongly modified by controlling the defect distribution through annealing and ion irradiation treatments. In particular, the splitting of vacancy clusters and triple defects into mono-vacancies by irradiation accelerates thermal diffusion, lowering the temperature necessary for re-ordering [J. Ehrler, et al., Acta Mater. 176 (2019) 167]. In case of B2 Fe50Rh50 thin films, ion irradiation induces a ferromagnetic behaviour in the initially antiferromagnetic thin films. The variation of open-volume defects during this transition has been tracked. We will demonstrate that irradiation induces open volume defects, whose concentration scales with ion fluence, providing insights on the types of defects associated with ferromagnetism in the Fe50Rh50 system.