Spin transfer torque magnetic tunnel junction with off-centered current flow

A memory device, comprising:

• a plurality of spin-transfer torque magnetic tunnel junctions, each in turn comprising:
• a layer stack with
• two magnetic layers, including a pinned layer and a free layer;
• and
• an insulating barrier layer between the two magnetic layers,
• wherein:
• each of the two magnetic layers has an out-of-plane magnetization orientation;
• and
• one or each of the pinned layer and the insulating barrier layer has an average diameter less than an average diameter of the free layer and is off-centered from a center of the free layer toward an edge of the layer stack for guiding an off-centered flow of spin-polarized current from one of the two magnetic layers to the other on application of a control voltage to the layer stack, wherein each average diameter is measured in a plane perpendicular to a stacking direction of the layer stack, whereby the junction is configured so as to initiate an asymmetrical switching of the magnetization orientation of the free layer on application of the control voltage;
• and
• means for selectively applying control voltages to one or more of the plurality of junctions.

A method of operation of a spin-transfer torque magnetic tunnel junction, the method comprising:

• providing the spin-transfer torque magnetic tunnel junction, the spin-transfer torque magnetic tunnel junction comprising:
• a layer stack with two magnetic layers, including a pinned layer and a free layer;
• and
• an insulating barrier layer between the two magnetic layers,
• wherein:
• each of the two magnetic layers has an out-of-plane magnetization orientation;
• and
• one or each of the pinned layer and the insulating barrier layer has an average diameter less than an average diameter of the free layer and is off-centered from a center of the free layer toward an edge of the layer stack for guiding an off-centered flow of spin-polarized current from one of the two magnetic layers to the other on application of a control voltage to the layer stack, wherein each average diameter is measured in a plane perpendicular to a stacking direction of the layer stack, whereby the junction is configured so as to initiate an asymmetrical switching of the magnetization orientation of the free layer on application of the control voltage;
• and
• generating an off-centered spin-polarized current flow from the pinned layer to the free layer, to initiate an asymmetrical switching of the magnetization orientation of the free layer, by applying a control voltage to the layer stack.