Spin Current Magnetoresistance Element Magnetic Field Cancellation

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Solution Overview

Problem

Integrated spin current magnetization rotation magnetoresistance effect elements face issues with magnetic field interference, leading to unstable magnetization and increased probability of magnetization reversal, affecting data retention and memory performance.

Innovation Solution

A spin current magnetization rotation magnetoresistance effect element is designed with a specific layered structure comprising a spin-orbit torque wiring layer, a first ferromagnetic layer, an antiferromagnetic coupling layer, a second ferromagnetic layer, a nonmagnetic layer, and a magnetization reference layer, where the product of the saturation magnetization and film thickness of the first ferromagnetic layer is greater than that of the second ferromagnetic layer, canceling out magnetic fields and stabilizing the magnetization reference layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a spin current magnetization rotation magnetoresistance effect element is integrated, then data writing speed is improved, but magnetic field interference increases causing unstable magnetization

Engineering Contradiction:

Improvedata writing speedVSAvoidmagnetization stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The magnetic recording layer is divided into two separate ferromagnetic layers (first and second ferromagnetic layers) with different magnetization directions. This segmentation allows the magnetic fields generated by each layer to cancel each other out, reducing overall magnetic field interference while maintaining fast data writing capability through spin-orbit torque.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first and second ferromagnetic layers are designed with asymmetric properties, specifically different products of saturation magnetization and film thickness. This asymmetry in magnetic moment magnitude enables effective magnetic field cancellation when the layers are configured with opposite magnetization directions, solving the stability issue in integrated structures.

Inventive Principle:

Principle #4Asymmetry

2Object-affected harmful factors

If magnetic field cancellation is achieved by increasing the first ferromagnetic layer thickness, then magnetic field interference is reduced, but device complexity increases

Engineering Contradiction:

Improvemagnetic field interferenceVSAvoidlayer structure complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Instead of simply increasing the thickness of the first ferromagnetic layer, the invention changes the magnetic moment parameter by adjusting the product of saturation magnetization and film thickness. This allows magnetic field cancellation to be achieved through material composition and thickness optimization rather than merely increasing geometric dimensions, thereby avoiding excessive device complexity.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration reduces the influence of magnetic fields on adjacent elements, enhances data stability, and allows for high-speed data writing with reduced power consumption, making it suitable for replacing SRAM with a nonvolatile memory.

Implementation Method 1

A spin current in a direction orthogonal to that of the current is generated so that the magnetization of a first ferromagnetic layer in contact with the spin-orbit torque wiring layer is inversed

Methodology Applied

Scientific EffectSpin-orbit interaction:

Implementation Method 2

A spin current in a direction orthogonal to that of the current is generated so that the magnetization of a first ferromagnetic layer in contact with the spin-orbit torque wiring layer is inversed

Methodology Applied

Scientific EffectRashba effect:

Implementation Method 3

a first ferromagnetic layer, an antiferromagnetic coupling layer, a second ferromagnetic layer

Methodology Applied

Scientific EffectAntiferromagnetic coupling:

Data Source

PatentUS10923649B2Spin current magnetization rotation magnetoresistance effect element, and magnetic memory

Publication Date: 2021.02.16 TDK CORP

AI summary

There is provided a spin current magnetization rotation magnetoresistance effect element that can reduce generation of a magnetic field influencing other elements.The spin current magnetization rotation magnetoresistance effect element in which a spin-orbit torque wiring layer, a first ferromagnetic layer, an antiferromagnetic coupling layer, a second ferromagnetic layer, a nonmagnetic layer, and a magnetization reference layer are disposed in an order, wherein a magnitude of the product of the saturation magnetization of the first ferromagnetic layer and the film thickness of the first ferromagnetic layer is larger than a magnitude of the product of the saturation magnetization of the second ferromagnetic layer and the film thickness of the second ferromagnetic layer.