Emerging memories

Which correctly describes the roles of the two magnetic layers in an MTJ?

  1. AOne is a reference layer with fixed magnetization; the other is a free layer whose direction is changed by writing
  2. BBoth layers' magnetizations are reversed on every write
  3. CBoth layers' magnetizations are always fixed
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Answer: A. One is a reference layer with fixed magnetization; the other is a free layer whose direction is changed by writing

One magnetic layer of an MTJ is the reference (pinned) layer, whose magnetization direction is fixed. The other is the free (storage) layer, whose magnetization can be reversed by writing. Whether the free layer is parallel or antiparallel to the reference layer stores a 0 or a 1.

  • A. Correct. It combines a reference layer and a free layer.
  • B. The reference layer's direction, which serves as the standard, is not changed.
  • C. If both were fixed, no information could be written.
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