Effects of the channel material parameters on the spin-torque critical current of lateral spin valves

• The effects of channel parameters on the spin-torque critical current are studied systematically.
• From the perspective of critical current, long diffusion length is not enough for an ideal channel material.
• The results show that spin transport in the channel plays a pivotal role in determining the critical current.

The lateral spin valve structures operated by the principle of spin- torque effect have shown great potentials for constructing the all- spin – logic. Like vertical spin valves, the problem of excessive spin-torque critical current also exists in lateral spin valves. Appropriate channel materials may reduce the spin-torque critical current, so finding the right channel material is a direction of many authors’ efforts over years. In this paper, the four-component distributed spin-circuit model is used to calculate the spin-polarized current which is transported from the polarizer (fixed layer) to the detector (free layer). The effects of channel material parameters on the spin-torque critical current in the free layer of the lateral spin valve are studied numerically by using the Landau–Lifshitz–Gilbert–Slonczewski equation. Based on the numerical results, the problem of whether graphene is a suitable channel material is discussed.

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