Toggling cell with four antiferromagnetically coupled ferromagnetic layers for high density MRAM with low switching current

Toggling MRAM with four antiferromagnetically (AF) coupled ferromagnetic (FM) layers is proposed. The AF coupling strength between the inner FM layers should be larger than between the others. The four-FM-layer toggle cell shows not only good thermal stability but also a large write margin even with a small spin flop field. The advanced toggle cell has the potential to decrease write current by half compared with the basic two-FM-layer cell and can improve MRAM scalability.