Dresden 2020 – wissenschaftliches Programm
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KFM 4.5: Vortrag
Montag, 16. März 2020, 16:40–17:00, HSZ 105
Non-invasive study of buried domain patterns in multiferroic bismuth ferrite — •Marvin Müller1, Yen-Lin Huang2, Ramamoorthy Ramesh2, Morgan Trassin1, and Manfred Fiebig1 — 1ETH Zurich, Switzerland — 2University of California, Berkeley, USA
Magnetoelectric (ME) multiferroic materials hosting coexisting and coupled electric and magnetic orders allow for low-energy control of magnetism and thus hold great promise for energy-efficient random-access memories and logic devices. In BiFeO3/Co0.9Fe0.1 heterostructures, room-temperature electric-field-induced reversal of the ferromagnetic magnetization has been recently achieved. Despite extensive studies on the ME coupling in BiFeO3, the switching dynamics remain elusive. The lack of direct experimental access to the ferroic properties of the buried material renders operando investigations challenging. Here, we probe the ferroelectric switching in the model system BiFeO3/Co0.9Fe0.1. We use spatially-resolved non-invasive optical second harmonic generation (SHG) to map the net polarization of the buried BiFeO3 layer after voltage application. Our results suggest the emergence of a strong net polarization with the first voltage pulse. Additional scanning probe microscopy is used to correlate this observation with the emergence of stripe-domain patterns with 71∘ domain walls. This work introduces SHG as an effective tool to non-invasively study buried ferroelectric domain states and thus opens novel pathways towards operando electro-optic studies on the dynamics in these coupled systems.