2019, Effect of the Low-resistance Tunnel Barriers Induced Inhomogeneous Spin Current Distribution in Graphene Crossed Configuration Lateral Spin Valve, AIP ADVANCES.

Abstract:

The non-local spin valve (NLSV) configuration compose of two ferromagnetic (FM) and non-magnetic (NM) channels, which is an effective method for determining spin injection and accumulation. Here, we report that a reversed non-local spin signal was detected by changing the voltage probe configurations in graphene (Py/MgO/Graphene/MgO/Py) lateral spin valves. The abnormal reversed spin-dependent non-local voltage is attributed to the non-uniform pinhole at the interface of the low-resistance tunnel barrier, which yields the charge current to flow through the detection electrode and return to the graphene channel. We demonstrate that the channel-width induced spin-polarized current inhomogeneity that significantly contributes to non-local resistance. A detailed description and simulated results of the tunnel junctions provide evidence for the reversal of the Non-local voltage sign induced by the low-resistance tunnel barriers.  Our work sheds light on the understanding of the spatial distribution of the spin current and the effect of the tunnel barrier, which are essential for the development of spintronic devices.

Keywords: Spin transport, spin injection, spin valve, spin-polarized current,tunnel barrier.

https://aip.scitation.org/doi/pdf/10.1063/1.5088200