Nonlocal spin transports in nanopillar-based lateral spin valve

Abstract

A different type lateral spin valve structure consisting of a pair of the closely located Permalloy nanopillars on a uniform copper film has been developed. From the bias-current and temperature dependences of the spin signal, the nanopillar lateral spin valve was found to have several advantages for generating the pure spin current over the conventional lateral spin valves. We also show that the limitation of the generating spin current can be enhanced by increasing the number of the spin injectors.

Geometrical dependence of spin current absorption into a ferromagnetic nanodot

“…3(a), the obtained spin signal using Py1 and Py4 is 0.37 mX, which is smaller than the value expected from the previous nanopillar lateral spin valve. 17 Moreover, as in Fig. 3(b), we obtain 0.26 mX, which is comparable to the spin signal in Fig.…”

“…However, the obtained spin signal was smaller than the previously reported device with a similar lateral dimension. 17 This is because the spin current distribution is affected by other ferromagnetic dots. To clarify the influence of the multi spin injectors and analyze the spin absorption efficiency due to the Py5, we evaluate the nonlocal spin valve signal with various probe configurations.…”

“…[11][12][13][14][15][16] To solve this issue, we have recently developed a different-type lateral spin valve, consisting of pillar-shaped ferromagnetic nanodots and a quasi-two-dimensional nonmagnetic film. 17,18 We showed that the Joule heating from the ferromagnetic injector is significantly suppressed in the nanopillar-based lateral spin valve because of the reduction of the volume of the ferromagnetic element in the current probe and the efficient heat sink effect of a two dimensional nonmagnetic film. Moreover, because of its geometrical flexibility, one can easily increase the number of the spin injectors, leading to the multi-terminal spin injection.…”

Observation of large spin accumulation voltages in nondegenerate Si spin devices due to spin drift effect: Experiments and theory

“…A theoretical calculation is also plotted in the same figure. Although the theoretical calculation reproduces the superlinear feature, it is maintained even above I = 6×10 -4 A. One possible origin of the sublinear feature is degradation of the spin transport properties e.g., spin polarization, spin lifetime, and so on, due to device heating [67,68]. In contrast, in the degenerate Si-and Cu-based LSVs, a weak superlinear relationship and a linear relationship were obtained, respectively, which were well reproduced by the theoretical curves.…”

Impact of interface properties on spin accumulation in dual-injection lateral spin valves

“…Nonoguchi et al showed multi-terminal LSVs with NiFe/Cu junctions. 9 However, the enhancement factor of the spin accumulation in the multi-terminal scheme compared with that of a conventional structure is unclear because the spin accumulation could be reduced by increasing the number of Ohmic contacts via spin absorption effects. 10,11 In this Letter, we address the impact of the interfacial properties on the enhancement of the spin accumulation and spin injection efficiency in the non-magnets in LSVs with dual injectors (DLSVs).…”