Spin-Orbit Torque Wiring With Heusler Alloys for Lower Write Current

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Solution Overview

Problem

Existing magnetoresistance effect elements face challenges in reducing the reversal current density for efficient spin current generation, which is essential for improving driving efficiency and extending the lifespan of these elements.

Innovation Solution

A spin-orbit-torque magnetization rotating element and magnetoresistance effect element utilizing a spin-orbit torque wiring made of specific Heusler alloys and non-magnetic materials, which efficiently generates a spin current through the spin Hall effect, reducing the need for high current densities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a magnetoresistive layer with perpendicular magnetic anisotropy is used to achieve high storage density and non-volatility, then data retention and energy efficiency are improved, but the write margin is insufficient and variability in switching characteristics increases

Engineering Contradiction:

Improvedata retentionVSAvoidswitching characteristic variability

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

A mediator layer with specific magnetic anisotropy is introduced between the reference layer and the magnetoresistive layer. This mediator layer acts as an intermediary that stabilizes the magnetic interaction, reducing variability in switching characteristics while maintaining the perpendicular magnetic anisotropy benefits for data retention.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention modifies the magnetic anisotropy parameters of the mediator layer to optimize the coupling between layers. By adjusting the thickness and material composition of the mediator layer, the magnetic anisotropy energy is tuned to reduce switching variability without compromising the high storage density and non-volatility of the perpendicular magnetization structure.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If conventional current through magnetoresistance effect elements is used for writing data, then the structure is simple, but power consumption is high and cannot meet requirements for large-capacity, low-power memory

Engineering Contradiction:

Improvewrite structure simplicityVSAvoidpower consumption

Core Design Contradiction:

Device complexityVSUse of energy by moving object

Solution Approach 1:

The invention replaces the conventional electrical current writing mechanism with a spin-orbit torque mechanism. Instead of using high-current electrical writing, the system utilizes spin-polarized current generated by a separate read element to write data to adjacent storage elements, significantly reducing power consumption while maintaining structural simplicity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The read element serves dual functions: it reads data from storage elements and simultaneously generates spin-polarized current to write data to other storage elements. This multi-functionality eliminates the need for separate write elements, reducing overall device complexity while achieving low-power operation.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Use of energy by moving object

If spin transfer torque is used for writing, then power consumption is reduced compared to conventional current, but the write current is still insufficient for practical applications

Engineering Contradiction:

Improvepower consumptionVSAvoidwrite current magnitude

Core Design Contradiction:

Use of energy by moving objectVSPower

Solution Approach 1:

The invention changes the writing mechanism from spin transfer torque to spin-orbit torque by introducing a mediator layer with specific magnetic properties. This parameter change in the writing mechanism enables much higher write currents to be achieved with the same applied current, making the write operation practical for large-capacity memory applications while maintaining low overall power consumption.

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

The proposed solution enables efficient generation of spin currents with reduced current density, enhancing the driving efficiency and extending the lifespan of these elements.

Implementation Method 1

a first magnetoresistive layer having a perpendicular magnetic anisotropy

Methodology Applied

Scientific EffectPerpendicular magnetic anisotropy: Magnetic Hysteresis

Implementation Method 2

a spin injection layer for injecting a spin current into the first magnetoresistive layer; a mediator layer having a specific magnetic anisotropy disposed between the spin injection layer and the first magnetoresistive layer

Methodology Applied

Scientific EffectSpin Hall Effect: Hall Effect

Implementation Method 3

Spin orbit torque type magnetoresistance effect element

Methodology Applied

Scientific EffectTunnel Magnetoresistance: Magnetoresistance

Data Source

PatentEP3758070B1Spin orbit torque type magnetization rotational element, spin orbit torque type magnetoresistance effect element and magnetic memory

Publication Date: 2026.04.22 TDK CORP

Figure 1~2B
Figure 2C~2E
Figure 2F~3

AI summary

This spin-orbit-torque magnetization rotating element includes a spin-orbit torque wiring extending in a first direction and a first ferromagnetic layer laminated on the spin-orbit torque wiring, wherein the spin-orbit torque wiring includes a compound represented by XYZ or X2YZ with respect to a stoichiometric composition.