The present invention generally relates to the field of magnetic devices for
memory cells that can serve as non-volatile memory. More specifically, the present
invention describes a high speed and low power method by which a spin polarized
electrical current can be used to control and switch the magnetization direction
of a magnetic region in such a device. The magnetic device comprises a pinned magnetic
layer with a fixed magnetization direction, a free magnetic layer with a free magnetization
direction, and a read-out magnetic layer with a fixed magnetization direction.
The pinned magnetic layer and the free magnetic layer are separated by a non-magnetic
layer, and the free magnetic layer and the read-out magnetic layer are separated
by another non-magnetic layer. The magnetization directions of the pinned and free
layers generally do not point along the same axis. The non-magnetic layers minimize
the magnetic interaction between the magnetic layers. A current is applied to the
device to induce a torque that alters the magnetic state of the device so that
it can act as a magnetic memory for writing information. The resistance, which
depends on the magnetic state of the device, is measured to thereby read out the
information stored in the device.