Naturally Oxidized FeCo as a Magnetic Coupling Layer for Electrically Isolated Read/Write Paths in mLogic

Abstract

Recently, a nonvolatile, low power circuit scheme based on current-induced domain wall motion and perpendicular magnetic tunnel junctions known as mLogic has been proposed that requires electrically isolated, magnetically coupled read and write paths. Here, we suggest naturally oxidized FeCo for the magnetic coupling layer. Relevant properties of the FeCo-oxide were evaluated by a preliminary investigation of [FeCo/FeCo-Oxide] <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</sub> artificial superlattices. It is found that FeCo thin films form an insulating 11 Å passivating oxide layer with a magnetization of 500 emu/cc. Experimental measurements show that FeCo-oxide can couple two perpendicular FeCoB layers with a coupling strength greater than 0.35 ergs/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .