Regensburg 2019 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 53: Magnetic Heuslers, half-metals and oxides
MA 53.1: Vortrag
Freitag, 5. April 2019, 09:30–09:45, H33
In-situ imaging of martensitic phase transitions in thin films of NiMnGa — •Bruno Weise1, Sebastian Fähler1, Kornelius Nielsch1,2, and Anja Waske1,3 — 1Leibniz Institute of Solid State and Materials Research (IFW), Dresden — 2Technische Universität Dresden — 3Federal Institute for Materials Research and Testing (BAM), Berlin
In magnetocaloric material, extrinsic sample properties affect the phase transition remarkable. In recent studies it was found that e.g. the surface morphology [1] as well as defects on the surface [2] have a significant influence on nucleation and growth of the magnetocaloric phase. With this work, studying NiMnGa thin films, we show the temperature dependent growth of martensite.
The microstructure of NiMnGa thin films is monitored by scanning electron microscopy equipped with a custom-built temperature stage. This set-up allows in-situ imaging of the temperature-induced phase transition. Advanced image analysis is used to determine the phase fractions and is compared to magnetic measurements. With in-situ investigation of the transformation of both, type X and Y martensite, the impact of external influences on the martensite growth is assessed.
[1] A. Waske, et al., APL Mater. 4, 106101 (2016)
[2] R. Niemann, et al., APL Mater. 4, 064101 (2016)