Figure 1

Scanning electron imaging (SEM) of Py/Au lateral spin valve (LSV) nanodevices characterized by (a) a lateral confined geometry and (b) standard open geometry (channel extending to a distance much longer than the spin diffusion length on both sides). (c) Sketches of the current and voltage contacts to measure local spin signals (MR) in confined (left) or open (right) geometry and nonlocal spin signals (center). The Q point is the central point of the channel between the two ferromagnetic contacts.Reuse & Permissions

Figure 2

$V/I=\Delta R$ vs magnetic field at 77 K for a Py/Au LSV with $L=200$ nm for the distance between the two ferromagnetic contacts. The blue dotted curve corresponds to an open channel whereas the red curve with triangles corresponds to a confined channel (the blue curve was shifted upward for clarity). The nonlocal (NL) signal obtained for the open channel is displayed in the inset of (a). (b) Local (MR) spin signals for confined (red triangles) or open (blue dots) LSV and nonlocal spin signals (green rectangles) as a function of the distance $L$ between the ferromagnetic stripe injector ($F1$) and ferromagnetic stripe detector ($F2$). Data were recorded at 77 K (liquid nitrogen). The dashed lines represent the fit obtained by introducing $l_{sf}^N=98$ nm in the theoretical expressions of the spin signal; see Eqs. (1) and (2) and the text.Reuse & Permissions

Figure 3

(a) The magnetoresistance ratio $\Delta R/R_F$ calculated for $O$ and $C$ structures and (b) the corresponding amplification factor between $O$ and $C$, $A=\Delta R_C/\Delta R_O$. These are plotted vs $R_F/R_N$ for different values of the distance L between $F1$ and $F2$: (1) $L/l_{sf}^N=0.1$, (2) $L/l_{sf}^N=1$, (3) $L/l_{sf}^N=2$, and (4) $L/l_{sf}^N=3$. The arrows indicate the values of $R_F/R_N$ for Py/Au, Py/Cu, and Py/Al.Reuse & Permissions

Figure 4

(a) Current spin polarization (${\mathcal{P}}^{\uparrow \uparrow }$) in the magnetic parallel state at point $Q$ and (b) amplification of ${\mathcal{P}}^{\uparrow \uparrow }$ for confined systems vs $R_F/R_N$. (c) Spin accumulation $\Delta {\mu }^{\uparrow \downarrow }$ in the magnetic antiparallel state at point $Q$ and (d) amplification of $\Delta {\mu }^{\uparrow \downarrow }$ vs $R_F/R_N$ for different gap lengths. For all figures, the different values of $L/l_{sf}^N$ are indicated in (a).Reuse & Permissions