Sandisk Technologies Inc.

Western Digital Technologies, Inc.

Michael Ho

Zhigang Bai

Quang Le

Zhanjie Li

Paul Vanderheijden

Xiaoyong Liu

Thao Anh Nguyen

Hongquan Jiang

Yongchul Ahn

Lijie Guan

Suping Song

Changqing Shi

Yaguang Wei

Terence T Lam

Venkatesh Chembrolu

Supradeep Narayana

Jian-Gang Zhu

Anna Zheng

An apparatus is provided that includes an array including n rows and m columns of nodes, each row of nodes coupled to one of n first conductive lines, each column of nodes coupled to one of m second conductive lines, each node of the n rows and m columns of nodes including a spin orbit torque MRAM non-volatile memory cell configured to store a corresponding weight of an n×m array of weights each having a first weight value or a second weight value, and a control circuit configured to apply n input voltages each having a first input value or a second input value to corresponding n first conductive lines, the n input voltages corresponding to an n-element input vector. The spin orbit torque MRAM non-volatile memory cells are configured to generate m output currents at the m second conductive lines upon application of the n input voltages. The m output currents corresponding to a result of multiplying the input vector by the n×m array of weights.

Matrix-vector multiplication using SOT-based non-volatile memory cells

A MRAM device includes a magnetic tunnel junction containing a reference layer having a fixed magnetization direction, a free layer, and a nonmagnetic tunnel barrier layer located between the reference layer and the free layer, a negative-magnetic-anisotropy assist layer having negative magnetic anisotropy that provides an in-plane magnetization within a plane that is perpendicular to the fixed magnetization direction, and a first nonmagnetic spacer layer located between the free layer and the negative-magnetic-anisotropy assist layer.

Spin-transfer torque MRAM with a negative magnetic anisotropy assist layer and methods of operating the same

An apparatus is provided that includes an array including m rows and n columns of nodes. Each column of nodes is coupled to one of n first conductive lines, and each row of nodes is coupled to one of m second conductive lines. Each node of the m rows and n columns of nodes includes a spin orbit torque-based spin torque oscillator circuit configured to oscillate at a corresponding intrinsic frequency. The spin orbit torque-based spin torque oscillator circuits are configured to generate m output signals at the m second conductive lines upon application of n input signals to corresponding n first conductive lines. The n input signals correspond to an n-element input vector, and each input signal includes a corresponding input signal frequency. Each of the m output signals include frequency domain components at the input signal frequencies. The magnitudes of the frequency domain components at the input signal frequencies depend on a degree of synchronization between the input signal frequencies and the intrinsic frequencies.

SOT-based spin torque oscillators for oscillatory neural networks

A MRAM cell includes a magnetic tunnel junction containing a reference layer having a fixed magnetization direction, a free layer, and a nonmagnetic tunnel barrier layer located between the reference layer and the free layer, a spin torque oscillator stack, and a first nonmagnetic spacer layer located between the free layer and the spin torque oscillator stack.

Spin transfer torque MRAM with a spin torque oscillator stack and methods of making the same

An apparatus is provided that includes a magnetic tunnel junction, a magnetic assist layer coupled to the magnetic tunnel junction, a non-magnetic layer disposed between the free layer and the magnetic assist layer, and a spin Hall effect layer coupled to the magnetic assist layer. The magnetic tunnel junction includes a free layer in a plane, the free layer including a switchable magnetization direction perpendicular to the plane. The magnetic assist layer includes a magnetization direction parallel to the plane and free to rotate about an axis perpendicular to the plane.

Apparatus and methods for magnetic memory devices with magnetic assist layer

A MRAM device includes a spin valve containing a reference layer having a fixed magnetization direction, a free layer, and a nonmagnetic metallic barrier layer located between the reference layer and the free layer, a metallic assist structure configured to provide rotating spin transfer torque to the free layer to assist the free layer switching during programming, and a first nonmagnetic metallic spacer layer located between the free layer and the metallic assist structure.

Metallic magnetic memory devices for cryogenic operation and methods of operating the same

A magnetic head includes a main pole configured to serve as a first electrode, an upper pole containing a trailing magnetic shield configured to a serve as a second electrode, and an electrically conductive portion located in a trailing gap between the main pole and the trailing magnetic shield. The electrically conductive portion is not part of a spin torque oscillator stack, and the electrically conductive portion includes at least one electrically conductive, non-magnetic material layer. The main pole and the trailing magnetic shield are electrically shorted by the electrically conductive portion across the trailing gap between the main pole and the trailing magnetic shield such that an electrically conductive path is present between the main pole and the trailing magnetic shield through the electrically conductive portion.

Magnetic head with current assisted magnetic recording and method of making thereof

A magnetic head includes a main pole configured to serve as a first electrode, an upper pole containing a trailing magnetic shield configured to a serve as a second electrode, and a record element located in a trailing gap between the main pole and the trailing magnetic shield. The record element includes an electrically conductive, non-magnetic material portion which is not part of a spin torque oscillator stack. The main pole and the trailing magnetic shield are electrically shorted by the record element across the trailing gap between the main pole and the trailing magnetic shield such that an electrically conductive path is present between the main pole and the trailing magnetic shield through the record element.

A MRAM device includes a magnetic tunnel junction containing a reference layer having a fixed magnetization direction, a free layer, and a nonmagnetic tunnel barrier layer located between the reference layer and the free layer, a first magnetic assist layer, a second magnetic assist layer, an antiferromagnetic coupling spacer layer located between the first and second magnetic assist layers, and a first nonmagnetic spacer layer located between the free layer and the first magnetic assist layer. The antiferromagnetic coupling spacer layer is configured to provide antiferromagnetic coupling between a first magnetization direction of the first magnetic assist layer and a second magnetization direction of the second magnetic assist layer.

Spin-transfer torque MRAM with magnetically coupled assist layers and methods of operating the same

A MRAM cell includes a magnetic tunnel junction containing a reference layer having a fixed magnetization direction, a free layer, and a nonmagnetic tunnel barrier layer located between the reference layer and the free layer, a spin torque oscillator stack, and a first nonmagnetic spacer layer located between the free layer and the a spin torque oscillator stack.

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Redwood City, CA, United States of America

Michael Ho