Spin-transfer torque (STT) is a phenomenon that occurs in spintronics, a field of electronics that exploits the intrinsic spin of electrons, in addition to their charge, to process and store information. In conventional electronics, information is stored in binary states (0s and 1s) represented by electric charge. In spintronics, the spin state of electrons (up or down) can also be used to represent information.
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Introduction to Spintronics by Aurélien Manchon (2020) spin-transfer torque section
. Source. Describes how how spin-transfer torque was used in magnetoresistive RAM
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