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Schematic drawing of the organic GMR device. From top to bottom: Co ferromagnetic top electrode (20 nm), AlOx tunnel barrier (2.5 nm), Alq3 spin transporting organic semiconductor layer (200 nm), La0.7Sr0.3MnO3 bottom ferromagnetic electrode (20 nm). The active area is 1 × 1 mm2. A current I is driven through the device, and a voltage V is measured. B is the applied magnetic field, at angle θ with the plane of the device.
Resistance in the parallel (P) and antiparallel (AP) state of the device, with the magnetic field applied at angle θ = 90° from the plane of the device. The top left inset shows the MR when the field is applied in the plane of the device, while the inset to the top right shows the complete MR for θ = 90°. The linear behavior at high field is due to the tilting out of plane of the magnetization of the electrodes.
MR at θ = 0, θ = 45°, and θ = 60° in a different resistive state from that in Figure 2 . In (a) and (c) the boxes are a schematic representation of the device as the combination of two parallel sub-devices. In each box, the arrows indicate the orientations of the magnetization in each sub-electrode. Each sub-electrode has a different coercive field. (b) Leftward magnetic field sweep. The numbers between the parentheses indicate the resistance level and correspond to the magnetization configuration indicated by the same number in (a). (c) Rightward magnetic field sweep. The numbers between parenthesis have the same meaning as above. The unusual look of the MR for θ = 60° is due to the fact that one of the switching fields exceeds the available range.
Hysteresis loops of a LSMO 20 nm thick film obtained by SQUID magnetometry at 100 K. The loop with square symbols corresponds to the magnetic field being applied in the plane of the film, the one with triangles to the field at θ = 45° with the plane and the circles to the field at θ = 90°. At θ = 90° and 20 mT the magnetization of the film is tilted out of plane by about 6%.
Hysteresis loops for a 20 nm thick Co film grown on a AlOx(2.5 nm)/Alq3 (50 nm)/Si, measured in a SQUID magnetometer at 100 K. The magnetic field was applied at θ = 0 (squares), θ = 45° (triangles), and θ = 90° (circles) from the plane of the device. At θ = 90° and 20 mT the magnetization is tilted out of plane by 1%.
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