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.