Berlin 2018 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 7: Battery Materials
MM 7.5: Talk
Monday, March 12, 2018, 12:45–13:00, H 0106
Conduction EPR spectroscopy with applied current — •Léonard Kröll1, Arvid Niemöller1, Peter Jakes1, Josef Granwehr1,2, and Rüdiger-A. Eichel1,3 — 1Institute of Energy and Climate Research - Fundamental Electrochemistry (IEK-9), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — 2Institut für Technische und Makromolekulare Chemie (ITMC), RWTH Aachen University, 52056 Aachen, Germany — 3Institut für physikalische Chemie (IPC), RWTH Aachen University, 52074 Aachen, Germany
The EPR signal evolution of a metallic lithium sample under a direct current (DC) has been investigated. The data show a significant change of the EPR signal. The Dysonian signal splits up at a threshold value resulting in two peaks with lower intensities.
Theoretical considerations show that the observation arises from the magnetic field induced by the DC. This field Bj interacts with the magnetization generating spins in two ways depending on the position of the spins in the sample. Firstly, Bj in- or decreases the main field B0 leading to two peaks. Secondly, the interaction field B1, which induces the spin flips, is modified. The direction of the DC determines if the on- or the off-resonance part of B1 is increased by Bj. In the first case the spin flipping process is strengthen, whereas in the second case it is not affected. Both factors together leads to an asymmetry in the signal originated by the direction of the DC.
In order to allow a comparison of the measured with the calculated data, the effect of the diffusion of the spin carrying electrons in the metal has to be incorporated. The results are shown within this work.