Selective Tuning of Perpendicular Magnetic Anisotropy and Dzyaloshinskii-Moriya Interaction in Heterostructures Compatible with Magnetic Tunnel Junctions

Abstract

Chirally coupled magnetic tunnel junctions (MTJs) have been proposed as a route toward compact spin logic architectures. Micromagnetic simulations indeed show that chiral coupling between adjacent MTJs with perpendicular magnetic anisotropy (PMA) can be achieved through an in‐plane (IP) interconnection mediated by the Dzyaloshinskii–Moriya interaction, eliminating the need for current‐driven domain‐wall motion. Nevertheless, experimental implementation of this concept requires precise manipulation of PMA to define IP interconnections between MTJs, as well as independent control of DMI to ensure reliable coupling. Here, we introduce a hybrid free layer (HFL) stack comprising an Ir/Co bottom layer and a CoFeB/MgO top layer providing PMA. We show that ultrathin Pt insertion layers at the Ir/Co interface provide an effective means to tune the DMI without affecting PMA, enabling independent control of both properties. Finally, we develop an ion beam etching (IBE) process on a 300‐mm platform that selectively suppresses the CoFeB/MgO contribution to PMA, thereby converting the stack to IP magnetization. This approach enables the manipulation of the PMA of the interconnecting free layer during MTJ patterning, providing a scalable pathway for the fabrication of chirally coupled MTJs.