Hgst Netherlands, B.v.

Sandisk Technologies Inc.

Western Digital Technologies, Inc.

Young-Suk Choi

Jeffrey Childress

Matthew Joseph Carey

John C Read

Won Ho Choi

Neil Smith

Brian Rodrick York

Shekar B Chandrashekariaih

Neil Leslie Robertson

Kurt A Rubin

Jordan Asher Katine

Yang Li

Patrick Braganca

Goran Mihajlovic

Derek Stewart

Elizabeth Ann Brinkman

Tomoya Nakatani

Apparatuses, systems, and methods are disclosed for magnetoresistive random access memory. A magnetic tunnel junction (MTJ) for storing data may include a reference layer. A free layer of an MTJ may be separated from a reference layer by a barrier layer. A free layer may be configured such that one or more resistance states for an MTJ correspond to one or more positions of a magnetic domain wall within the free layer. A domain stabilization layer may be coupled to a portion of a free layer, and may be configured to prevent migration of a domain wall into the portion of the free layer.

Multi-resistance MRAM

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.

Neuron circuit structures are presented which employ magnetic tunnel junction (MTJ) elements that change state probabilistically in response to application of electrical source currents that emulate synaptic activity. Some implementations form probabilistic neuron circuits using homogeneous perpendicular spin-transfer torque (STT) MTJ elements. These neuron circuits include a perpendicular STT reference MTJ element coupled via an electrical node with a perpendicular STT neuron MTJ element that can change state. The electrical node for each neuron circuit couples a neuron MTJ element or 'perturbation' element to a reference element, and also to an electrical current employed to influence probabilistic magnetization state changes in the perturbation MTJ element. A read current can be applied to the perturbation element to produce an output voltage at the electrical node indicative of a magnetization state of the perturbation element.

Probabilistic neuron circuits

Apparatuses, systems, and methods are disclosed for magnetoresistive random access memory. A magnetic tunnel junction for storing data includes a fixed layer, a barrier layer, and a composite free layer. A barrier layer is disposed between a fixed layer and a composite free layer. A composite free layer includes a ferromagnetic amorphous layer and an in-plane anisotropy free layer. A spin Hall effect (SHE) layer may be coupled to the composite free layer of the magnetic tunnel junction. The SHE layer may be configured such that an in-plane electric current within the SHE layer causes a spin current in the composite free layer.

Composite free layer for magnetoresistive random access memory

Apparatuses, systems, and methods are disclosed for magnetoresistive random access memory. A magnetic tunnel junction for storing data includes a fixed layer, a barrier layer, and a composite free layer. A barrier layer is disposed between a fixed layer and a composite free layer. A composite free layer includes an in-plane anisotropy free layer, a perpendicular magnetic anisotropy (PMA) inducing layer, and a ferromagnetic amorphous layer. A PMA-inducing layer may be disposed such that an in-plane anisotropy free layer is between a barrier layer and the PMA-inducing layer. A ferromagnetic amorphous layer may be disposed between an in-plane anisotropy free layer and a PMA-inducing layer.

A spin orbit torque magnetoresistive random access memory (SOT MRAM) cell includes a magnetic tunnel junction that contains a free layer having two bi-stable magnetization directions, a reference magnetic layer having a fixed magnetization direction, and a tunnel barrier layer located between the free layer and the reference layer, and a nonmagnetic spin Hall effect layer. The spin Hall effect layer may include an alternating stack of beta phase tungsten layers and noble metal nonmagnetic dusting layers. Alternatively or in addition, a hafnium layer may be located between the nonmagnetic spin Hall effect layer and the free layer.

Spin orbit torque magnetoresistive random access memory containing composite spin hall effect layer including beta phase tungsten

Embodiments of the present disclosure generally relate to memory devices having enhanced perpendicular magnetic anisotropy. The memory device includes a plurality of first leads, a plurality of second leads, and a plurality of memory cells having a plurality of magnetic layers and a tunneling barrier layer. An interfacial layer is incorporated in each memory cell between one of the magnetic layers and the tunneling barrier layer to enhance perpendicular magnetic anisotropy, while preserving high tunneling magnetoresistance.

Magnetoresistive effect devices having enhanced magnetic anisotropy

Embodiments disclosed herein generally relate to a magnetic head having an amorphous ferromagnetic reference layer. The ferromagnetic reference layer may have amorphous structure as a result of an amorphous ferromagnetic underlayer that the ferromagnetic reference layer is deposited thereon. The amorphous ferromagnetic reference layer enhances magnetoresistance, leading to an improved magnetic head.

Underlayer for reference layer of polycrystalline CPP GMR sensor stack

A disk drive includes a disk including a magnetizable layer of material, and a transducer. The transducer has a read element that includes a first shield layer, a pinned layer, a metallic spacer, an AP (anti-parallel) free layer, and a second shield layer. The pinned layer has a surface area which is greater than the area of the AP free layer. The read element also includes an anti-ferromagnetic layer for substantially fixing the magnetic orientation of a plurality of domains in the pinned layer. The ferromagnetic layer is adjacent the pinned layer. The pinned layer, and the anti-ferromagnetic layer both have surface areas which are greater than the area associated with the AP free layer. The anti-ferromagnetic layer, in one embodiment, has a pinning strength in the range of 0.5 erg/cmto 1.5 erg/cm.

Giant magneto resistive sensor and method for making same

In one embodiment, a device includes a reference layer, a free layer positioned above the reference layer, and a spacer layer positioned between the reference layer and the free layer, the spacer layer providing a gap between the reference layer and the free layer, wherein the reference layer extends beyond a rear extent of the free layer in an element height direction perpendicular to a media-facing surface of the device, and wherein a rear portion of the spacer layer that extends beyond the rear extent of the free layer has an increased resistivity in comparison with a resistivity of a rest of the spacer layer. In other embodiments, a method for forming the device is presented, along with other device structures having an extended pinned layer (EPL).

Magnetic recording head with CPP-GMR spin-valve sensor and extended pinned layer

A current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) has a multilayer reference layer containing a Heusler alloy. The multilayer reference layer includes a crystalline non-Heusler alloy ferromagnetic layer on an antiferromagnetic layer, a Heusler alloy layer, and an intermediate crystalline non-Heusler alloy of the form CoFeX, where X is one or more of Ge, Al, Si and Ga, located between the non-Heusler alloy layer and the Heusler alloy layer. The CoFeX alloy layer has a composition (CoFe)Xwhere y is between about 10 and 90 atomic percent, and z is between about 50 and 90 atomic percent. The CoFeX alloy layer induces very strong pinning, which greatly lessens the likelihood of magnetic instability by the spin polarized electron flow from the free layer to the reference layer.

Current-perpendicular-to-the-plane (CPP) magnetoresistive sensor with multilayer reference layer including a crystalline CoFeX layer and a Heusler alloy layer

A method for making a current-perpendicular-to-the-plane (CPP) magnetoresistive (MR) sensor that has a reference layer with low coercivity includes first depositing, within a vacuum chamber, a seed layer and an antiferromagnetic layer on a substrate without the application of heat. The substrate with deposited layers is then heated to between 200-600&#xb0; C. for between 1 to 120 minutes. The substrate with deposited layers is then cooled, preferably to room temperature (i.e., below 50&#xb0; C., but to at least below 100&#xb0; C., in the vacuum chamber. After cooling of the antiferromagnetic layer, the ferromagnetic reference layer is deposited on the antiferromagnetic layer. Then the substrate with deposited layers is removed from the vacuum chamber and subjected to a second annealing, in the presence of a magnetic field, by heating to a temperature between 200-400&#xb0; C. for between 0.5-50 hours.

Growing community of inventors

Los Gatos, CA, United States of America

Young-Suk Choi