Multi-resistance mram
AssigneeSanDisk Technologies LLC
InventorsYOUNG-SUK CHOI, WON HO CHOI
Life of this patent
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Abstract
Apparatuses, systems, and methods are disclosed for magnetoresistive random access memory. A magnetic tunnel junction for storing data may include a reference layer, a barrier layer, and a free layer. A barrier layer may be disposed between a reference layer and a free layer. A free layer may include a nucleation region and an arm. A nucleation region may be configured to form a magnetic domain wall. An arm may be narrower than a nucleation region and may extend from the nucleation region. An arm may include a plurality of pinning sites formed at predetermined locations along the arm for pinning a domain wall.
Claims25
An apparatus comprising:
- a magnetic tunnel junction (MTJ) for storing data, the magnetic tunnel junction comprising a reference layer, a barrier layer, and a free layer, the barrier layer disposed between the reference layer and the free layer, the free layer comprising:
- a nucleation region configured to form a magnetic domain wall;
- and
- an arm, narrower than the nucleation region and extending from the nucleation region, the arm comprising a plurality of pinning sites formed at predetermined locations along the arm for pinning the domain wall.
A system comprising:
- a neuromorphic computing die, the neuromorphic computing die comprising a plurality of artificial neurons and a synapse array of multi-state magnetic memory cells coupling the artificial neurons, wherein a magnetic storage layer for a multi-state magnetic memory cell comprises:
- a pad-shaped region for forming a magnetic domain wall;
- and
- one or more arms, narrower than the pad-shaped region and extending from the pad-shaped region, the one or more arms comprising a plurality of notches for pinning the domain wall.
An apparatus comprising:
- means for forming a magnetic domain wall in a free layer for a magnetic tunnel junction;
- and
- means for pinning the domain wall at one or more predetermined locations along one or more arms in the free layer.
An apparatus comprising:
- a magnetoresistive random access memory (MUM) die, the MRAM die comprising a plurality of memory cells, a memory cell comprising a fixed layer, a barrier layer, and a free layer, the barrier layer disposed between the fixed layer and the free layer, the free layer comprising:
- a nucleation region configured to form a magnetic domain wall in response to a write current;
- a wall extension region configured to provide a plurality of resistance states for the memory cell corresponding to positions of the domain wall within the wall extension region;
- and
- a plurality of pinning sites formed at predetermined locations in the wall extension region and configured to pin the domain wall such that the domain wall migrates from one pinning site to a subsequent pinning site in response to an increased write current.
A method comprising:
- applying a first write current to a magnetic tunnel junction to form a magnetic domain wall in a nucleation region of a free layer of the magnetic tunnel junction, wherein the domain wall migrates to a first pinning site in the free layer;
- applying a second write current to the magnetic tunnel junction to move the domain wall from the first pinning site to a second pinning site in the free layer, wherein the pinning sites are formed at predetermined locations in the free layer.
Dependencies are inferred from the claim text.