SKM 2023 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 3: Magnetic Materials for Efficient Energy Conversion
MA 3.4: Vortrag
Montag, 27. März 2023, 10:15–10:30, HSZ 401
A thorough TEM investigation of B2 ordered FeRh (50/50) alloy — •Esmaeil Adabifiroozjaei1, Nagaarjhuna Kani1,2, Robert Winkler1, Tianshu Jiang1, Oscar Recalde1, Alexander Zintler1, Alisa Chirkova2, Konstantin Skokov2, Oliver Gutfleisch2, and Leopoldo Molina Luna1 — 1Advanced Electron Microscopy, Department of Materials- and Earth Sciences, Technical University of Darmstadt, Germany — 2Functional Materials, Department of Materials- and Earth Sciences, Technical University of Darmstadt, Darmstadt, Germany
Fe50Rh50 alloys are known to have a B2 structure with an antiferromagnetic to ferromagnetic transition at near room temperature. Since this alloy can be considered as betta alloy (CdAu, TiNi, Fe-C, etc), it is expected to present a pre-martensite structure followed by a martensite structure upon cooling at cryogenic temperature. The martensite was also predicted by extensive first principal calculations. However, so far, no evidence has been given regarding the formation of either pre-martensite or martensite structures in the Fe50Rh50 alloy. Here, we use various TEM techniques (including CTEM, HRTEM, STEM (HAADF), and EDS) to investigate the FeRh 50/50 alloy and demonstrate that although the structure of the alloy matches the B2 BCC structure, there is systematic modulation along certain reflexes (100 and 110). We believe that the existence of such ordered modulation along certain directions are indicative of a pre-martensite structure.