Scaling limits on all-spin logic

Scaling limits on all-spin logic (ASL) are theoretically studied using the spin circuit theory and the stochastic Landau-Lifshitz-Gilbert equation under the macrospin approximation. It is found that as ASL circuits are scaled, the device delay significantly increases due to a stronger dipole coupling between the input and the output magnets. The effect of the dipole interaction can be mitigated by increasing the input current and by using smaller magnets with stronger material anisotropy and weaker saturation magnetization. Furthermore, the presence of the leakage current modifies the device delay. Finally, both delay and energy of ASL dramatically increase as the shunt path is shortened. Possible solutions to eliminate the leakage current and the shunt path are discussed.