Regensburg 2019 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 57: Organic Electronics and Photovoltaics IV - Excitonic Properties and Light-Emitting Devices

CPP 57.6: Vortrag

Donnerstag, 4. April 2019, 16:15–16:30, H18

Detecting magnetic resonance in Earth's magnetic field — •Sebastian Milster, Tobias Grünbaum, Simon Kurrmann, Hermann Kraus, Sebastian Bange, and John M. Lupton — Universität Regensburg,Institut für Experimentelle und Angewandte Physik, Universitätsstraße 31, 93053 Regensburg, Germany

Electron paramagnetic resonance in OLEDs [1] at magnetic field strengths comparable to Earth's field offers a way to model the migratory orientation ability of some birds [2] to a certain extent in a laboratory setting.

With the expected resonance position at a field of approximately 44 microtesla for a frequency of 1.315 MHz [3], even small stray fields as well as Earth's magnetic field have a rather large effect and create a shift on the magnetic field axis, depending on their orientation to the external applied field. As a consequence, the expected resonance peaks partially overlap with other effects in the device, thus becoming almost unresolvable. By compensating all parasitic fields with a three-dimensional arrangement of Helmholtz coils, it is possible to nullify the shifting effects. Following this, the resonances become resolvable for frequencies even in the low MHz-regime. By optimizing the experimental parameters preliminary results are presented, showing EPR at a frequency of 1.315 MHz, in resonance with the Zeeman splitting induced by Earth's field.

[1] H. Kraus et al., Phys. Rev. B 95, 241201(R)(2017)

[2] W. Wiltschko et al., Science 176, 71-77 (1972)

[3] W. Baker et al., Nat. Commun. 3, 898 (2012)