(a) Schematic drawing of a Ni/V2O3/Py device, side view, showing different layers; and (b) microscope image of a device, view from the top. Direction of applied magnetic field, H, as well as electrodes used for applying current and measuring voltage are indicated. (c) Geometry of the simulated device. Red dashed contour indicates the location of the V2O3 layer at the intersection of the Ni (blue) and Au (yellow) contacts.
R vs. T of the devices with 3 different V2O3 thicknesses: 65 nm (black solid squares), 39 nm (green empty circles), and 26 nm (orange solid triangles), showing the changes of the MITs with thickness.
Coercivities, HC , of bottom Ni layer (black solid squares), top Py layer (empty red circles), and top Ni layer for Ni/V2O3/Ni sample (blue empty triangles). Inset: example AMR of the bottom Ni contact at 20 K. Solid and dashed lines show positive and negative magnetic field sweeps, respectively. The coercivities are given at the peaks positions, indicated by the arrows.
(a) Temperature evolution of ΔR(H) for Ni(40)/V2O3(65)/Py(15) device (positive field sweep only). Two light-green (light-grey) vertical curves indicate the reversal fields of FM layers (also shown on Figure 3 ). (b) 5 examples of ΔR(H) for 5 different T (positive field sweep only—indicated by black arrows), corresponding to the black horizontal lines on (a). Each curve is offset by 0.01 Ω. The magnitude of the SV effect, ΔRSV , is taken as the resistance difference between the plateau height and the extrapolation of the smooth background, demonstrated by the dashed lines on the 30 K slice. The magnitude of AMR effect, ΔRAMR , is taken as a peak to peak position, demonstrated by the dashed lines on the 260 K slice.
Magnetoresistance measurements (a) at 20 K and (b) at 300 K for three different samples (positive field sweep only—indicated by black arrows). Red solid line corresponds to a regular sample with Py as the top ferromagnetic layer, blue dotted-dashed line correspond to a sample with top Ni layer, black dashed line—top Nb layer. Thickness of V2O3 layer is 44 nm in samples with Py and Nb, and 65 nm in sample with Ni. Green dotted and arrow lines show how the ΔRSV is extracted from the graph for the sample with Py.
ΔRSV /Rsat and ΔRAMR /Rsat as a function of V2O3 thickness. Solid blue squares correspond to the spin-valve effect at 20 K, empty magenta circles correspond to AMR effect at 300 K. The error bars indicate the standard deviation of the magnetoresistance measured for different devices with the same V2O3 thickness. Straight lines are guides to the eye, highlighting the difference between low and high temperature MR.
(a) Equivalent resistance model of the FM/NM/FM device for P and AP states. (b) Schematics of a FM/NM/FM device with x-axis perpendicular to the layers.
(a) Example of a measured resistance as a function of temperature for a real device. (b) Resistivity of V2O3 obtained by matching the simulated and measured resistances for temperatures indicated by red circles on (a).
(a) 20 K out-of-plane component of the current density across the V2O3 layer, corresponding to the area of the device marked by red dashed contour in Figure 1(c) . (b) Same as (a) but at 300 K. Color-scale of the current density is the same for both (a) and (b).
Relative contributions of V2O3 (black squares), Ni (red circles), and Au (violet stars) as a function of temperature.
Dependence of simulated ΔR/Rsim on temperature. This simulates the expected temperature dependence of ΔRSV /Rsat .
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