Extended Data Figure 9: Description of the magnetoresistance in relation to the domain structure of the unpinned (not in contact with BiFeO3) and pinned (in contact with BiFeO3) Co0.9Fe0.1 layers. | Nature

Extended Data Figure 9: Description of the magnetoresistance in relation to the domain structure of the unpinned (not in contact with BiFeO3) and pinned (in contact with BiFeO3) Co0.9Fe0.1 layers.

From: Deterministic switching of ferromagnetism at room temperature using an electric field

Extended Data Figure 9

As the magnetic field is swept from positive to negative field (open purple circles) along the easy axis of the device the domain structure of the pinned layer evolves from single-domain to a stripe-like structure and back to single-domain. The numbers correlate to the schematics of the domain structures to the spin-valve resistance. At large, positive magnetic field the free and pinned layers are monodomain with magnetizations parallel (1, light blue box) and the device resistance is low. At low, positive magnetic field the pinned layer breaks up into two domain variants owing to the exchange coupling with BiFeO3 while the free layer remains largely monodomain (2, black box). Both net magnetizations are parallel but the device resistance increases due to domain formation in the pinned layer. The purple box (3) encloses the region of magnetic field where the unpinned layer breaks up into domains during switching and the device resistance increases rapidly. In box 4 (red) the net magnetizations of the two layers are antiparallel but not fully antiparallel as the pinned layer is broken into domains and the device resistance is high. At high, negative magnetic field the device is again in a low-resistance state and the two layers are monodomain with parallel magnetization. A similar evolution of the domain structure occurs as the magnetic field is increased from negative to positive values (open red circles).

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