Anomalous Properties of Sub-10-nm Magnetic Tunneling Junctions

Magnetic Logic Devices have the advantage of non-volatility, radiation hardness, scalability down to the sub-10nm range, and three-dimensional (3D) integration capability. Despite these advantages, magnetic applications for information processing remain limited. The main stumbling block is the high energy required to switch information states in spin-based devices. Recently, the spin transfer torque (STT) effect has been introduced as a promising solution. STT based magnetic tunneling junctions (MTJs), use a spin polarized electric current to switch magnetic states. They are theorized to bring the switching energy down substantially. However, the switching current density remains in the order of 1 MA/cm2 in current STT-MTJ devices, with the smallest device reported to date around 10nm. This current density remains inadequately high for enabling a wide range of information processing applications. For this technology to be competitive in the near future it is critical to show that it could be favorably scaled into the sub-10-nm range. This is an intriguing size range that currently remains unexplored. Nanomagnetic devices may display promising characteristics that can make them superior to their semiconductor counterparts. Below 10nm the spin physics from the vii surface become dominate versus those due to volume. The goal is to understand the size dependence versus the switching current