Spin-torque memory with unidirectional write scheme
AssigneeSeagate Technology LLC
InventorsHaiwen Xi, Dexin Wang, Dimitar V. Dimitrov, Paul E. Anderson, Song S. Xue
Life of this patent
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Abstract
Spin torque magnetic memory elements that have a pinned layer, two free layers, and a current-blocking insulating layer proximate to at least one of the free layers. The resistive state (e.g., low resistance or high resistance) of the memory elements is altered by passing electric current through the element in one direction. In other words, to change from a low resistance to a high resistance, the direction of electric current is the same as to change from a high resistance to a low resistance. The elements have a unidirectional write scheme.
Claims20
A magnetic element comprising:
- a first ferromagnetic free layer having a magnetization orientation, a second ferromagnetic free layer having a magnetization orientation, and a nonmagnetic metallic spacer layer therebetween, wherein the first ferromagnetic layer and the second ferromagnetic layer are antiferromagnetically coupled to each other via an interlayer coupling field;
- a ferromagnetic pinned layer having a magnetization orientation pinned in a first direction;
- an insulative barrier layer between the pinned layer and the first free layer;
- and
- a current-blocking insulator layer proximate the second free layer, the current-blocking insulator having a via therethrough.
A magnetic element comprising:
- a first ferromagnetic free layer having a magnetization orientation, a second ferromagnetic free layer having a magnetization orientation, and a nonmagnetic metallic spacer layer therebetween, wherein the first ferromagnetic layer has a first magnetic coercivity and the second ferromagnetic layer has a second magnetic coercivity, and the second magnetic coercivity is larger than the first magnetic coercivity;
- a ferromagnetic pinned layer having a magnetization orientation pinned in a first direction;
- an insulative barrier layer between the pinned layer and the first free layer;
- and
- a current-blocking insulator layer proximate the second free layer, the current-blocking insulator having a via therethrough.
A method of altering a resistance of a memory cell comprising:
- providing a magnetic element having a low resistance, the magnetic element comprising:
- a first ferromagnetic free layer having a magnetization orientation, a second ferromagnetic free layer having a magnetization orientation, and a nonmagnetic metallic spacer layer therebetween, wherein the first ferromagnetic layer and the second ferromagnetic layer are antiferromagnetically coupled to each other via an interlayer coupling field;
- a ferromagnetic pinned layer having a magnetization orientation pinned in a first direction;
- an insulative barrier layer between the pinned layer and the first free layer;
- and
- a current-blocking insulator layer proximate the second free layer, the current-blocking insulator having a via therethrough.
- switching the magnetization orientation of the second free layer by passing a current in the second free layer through the via into the first free layer and the pinned layer;
- and
- switching the magnetization orientation of the first free layer by removing the current from the second free layer, and obtaining a high resistance across the magnetic element.
Dependencies are inferred from the claim text.