The effect of feature sizes on the characteristics of lateral spintronic devices have been investigated experimentally and theoretically. It is demonstrated that confining spin-transport in the active region of a device enhances magnitude of the spin-dependent response substantially. Numerical simulation of spin-transport corroborates the experimental observations. Device characteristics are found to be a strong function of spin-polarizer and analyzer dimensions. The response is observed to attain a peak value for an optimum device feature size, and this is seen to be a function of temperature. Spin dependent effects become weaker for very small and very large devices.

Most investigations of all spin logic (ASL) havebeen based on the mono -domain approximation of magnetization switching. The sensitive and stochastic nature of spin transfer torque (STT) switching creates pressing requirements for analyzing all spin logic from a micromagnetic perspective also. Hence, in this paper, all spin logic is studied from a micromagnetic perspective by developing a simulation framework that can capture diffusive spin transport. The spin transport model is calibrated from existing experimental results on non-local spin valve measurements. Then, using this framework, spin transfer torque switching is studied for inputoutput nano-magnets with in-plane and perpendicular magnetic anisotropy for all spin logic devices (ASLD). Precisely defined architecture and design constraints for such input-output nanomagnets are presented. Further, a previously proposed switching mechanism by driving the nano-magnet into a metastable state is also incorporated into micromagnetic framework. By using the aforementioned mechanism, the critical current required for spin transfer torque switching can be reduced to as low as 20μA. Moreover, graphene channel all spin logic device using tunnel contact at the injector is demonstrated for copy and invert logic operations.Index Terms-All spin logic (ASL), micromagnetic simulation, perpendicular magnetic anisotropy (PMA), spin transfer torque (STT), spin transport. area of high speed interconnects, low power VLSI design, nanoscale devices, carbon nanotube based designs, organic thin film transistor design and modelling, and spintronics based devices and circuits.