Progress in Magnetoresistive Memory: Magnetic Tunnel Junctions with a Composite Free Layer

Magnetoresistive memory is a candidate for future universal memory because of fast switching, high density, and non-volatility. However, improvement regarding the essential parameters such as thermal stability and switching current is still needed and finding alternative architectures for magnetic cell structures is of considerable importance for the success of magnetoresistive memory. A structure with a composite free layer displays significant switching time reduction without sacrificing the thermal stability. In this work we discuss the progress in development of structures with a composite free layer from first suggestions to structurally optimized cells. We compare the most important parameters of a newly proposed optimized structure with a composite free layer, which are the switching time, the thermal stability, and the switching energy barrier, with a conventional structure with a monolithic free layer.