SPIN TRANSFER TORQUE MAGNETIC MEMORY DEVICE USING MAGNETIC RESONANCE PRECESSION AND THE SPIN FILTERING EFFECT

摘要

The present invention relates to a magnetic memory device which additionally comprises a free magnetic layer constituting a horizontal direction variable magnetization layer having a fixed saturation magnetization value, whereby a switching current is markedly reduced as compared with conventional magnetic layers such that a high degree of integration of the device can be achieved and it is possible to lower a critical current density necessary for magnetization reversal thereby reducing the power consumption of the device. Also, a stray field effect occurring from a fixed magnetic layer is reduced such that a written magnetization data is thermally stable.

主权项

1. A magnetic memory device comprising:
a first fixed magnetic layer; a first free magnetic layer; a second free magnetic layer, a second fixed magnetic layer; a first non-magnetic layer disposed between the first fixed magnetic layer and the first free magnetic layer, a second non-magnetic layer disposed between the first free magnetic layer and the second free magnetic layer; and a third non-magnetic layer between the second free magnetic layer and the second fixed magnetic layer, wherein the first fixed magnetic layer is a thin layer formed of a material that has a fixed magnetization direction and that is magnetized in a perpendicular direction to a plane of the first fixed magnetic layer, wherein the first free magnetic layer is a thin layer formed of a material that has a magnetization direction which can be changed by an applied current and that is magnetized in a perpendicular direction to a plane of the first free magnetic layer, wherein the second free magnetic layer is a thin layer formed of a material that has a magnetization direction which can be changed by an applied current and that is magnetized in a horizontal direction to a plane of the second free magnetic layer, and wherein the second fixed magnetic layer is a thin layer formed of a material that has a fixed magnetization direction opposite to the first fixed magnetic layer and that is magnetized in a perpendicular direction to a plane of the second fixed magnetic layer.