Spin-transfer torque

STT-RAM also has the advantages of lower power consumption and better scalability than conventional magnetoresistive random-access memory (MRAM) which uses magnetic fields to flip the active elements.

[4] Hynix Semiconductor and Grandis formed a partnership in April 2008 to explore commercial development of STT-RAM technology.

[8] In 2011, Qualcomm presented a 1 Mbit Embedded STT-MRAM, manufactured in TSMC's 45 nm LP technology at the Symposium on VLSI Circuits.

In 2012 Everspin Technologies released the first commercially available DDR3 dual in-line memory module ST-MRAM which has a capacity of 64 Mb.

[10] In June 2019 Everspin Technologies started pilot production for 28 nm 1 Gb STT-MRAM chips.

A simple model of spin-transfer torque for two anti-aligned layers. Current flowing out of the fixed layer is spin-polarized. When it reaches the free layer the majority spins relax into lower-energy states of opposite spin, applying a torque to the free layer in the process.
A schematic diagram of a spin valve/magnetic tunnel junction. In a spin valve the spacer layer (purple) is metallic; in a magnetic tunnel junction it is insulating.