Regensburg 2019 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 28: Topical session (Symposium MM): Correlative and in-situ Microscopy in Materials Research

MM 28.6: Vortrag

Mittwoch, 3. April 2019, 17:15–17:30, H45

TEM in-situ investigation of relaxation and dynamics in amorphous FeNiP nanorods — •Katharina Spangenberg, Sven Hilke, Martin Peterlechner, and Gerhard Wilde — University of Münster, Institute of Material Physics

The method of electron correlation microscopy (ECM) using transmission electron microscopy (TEM) has been presented by He et al. to investigate dynamics and relaxation phenomena at the atomic scale. Using conventional TEM tilted dark field, the method has the ability to spatially resolve the dynamical processes in the supercooled liquid region of an amorphous alloy [1]. In the present study, the influence of the electron dose rate and non-equilibrium dynamics of amorphous FeNiP in nanostructured confinement are investigated at room temperature. A minimum dose rate is estimated to ensure proper signal-to-noise ratio. Non-equilibrium dynamics were investigated and analysed using the time autocorrelation function g2 (Δt) which can be fitted using a Kohlrausch-Williams-Watt (KWW) expression. ECM is used to calculate spatial distributions of relaxation times, represented by τ-maps. The FeNiP glass exhibits a phase separation, e.g. upon heat treatment. EDX measurements reveal a homogeneous composition or a bamboo structure of amorphous Fe-rich and Ni-rich layers. By comparing the atomic fluctuations with the local phase composition, a relation between phase separation and the time scales of the heterogeneous dynamics can be discussed.

[1] P. Zhang, J. J. Maldonis, Z. Liu, J. Schroers, & P. M. Voyles, Nature communications, 9(1), 1129, 2018