Interlayer dipolar coupling in CoFeB-based perpendicular magnetic tunnel junctions

Abstract

Interlayer dipolar coupling is an important aspect in magnetic switching devices from the application point of view. Here, we identify various sources affecting the interlayer dipolar coupling in CoFeB-based perpendicular magnetic tunnel junctions (pMTJs). By changing the MgO tunnel barrier layer thickness, we show that it plays a crucial role in controlling the dipolar coupling between the CoFeB reference and free layers and affects the magnetic properties of pMTJ. Moreover, changes in thickness of the bottom electrode layer affect the interlayer coupling strength and change the magnetic anisotropy of the free layer from perpendicular to in-plane direction. Furthermore, it is observed that the smaller the cell size of such MTJs, the more dominating the coupling strength which is formed by stray fields. These are some of the crucial parameters which need to be investigated during the device fabrication process for optimum device performance.