Asymmetric Composite Free Layers With Compensated Magnetization for Ultrahigh Density Integration of STT-MRAM

This paper analyzes the magnetization switching behavior of an asymmetric synthetic antiferromagnetic (AF) free layer for spin-transfer torque random access memory and numerically demonstrates thermally assisted magnetization switching. Optimization of the free-layer thickness and the magnetic properties enables successful magnetization switching while retaining the AF structure during the switching process. The thermal stability was improved by increasing the lateral aspect ratio of the free layers while also maintaining writability with a reduced current density under the thermal assistance.