Dual Spin Hall Effect Layers in Magnetic Write Gap

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Solution Overview

Problem

Existing magnetic recording technologies face challenges such as reduced writability as write head sizes shrink, reliability concerns, limited write gap thickness, and synchronization difficulties in Spin Hall Effect (SHE) assisted magnetic recording (SHAMR) designs, which affect overwrite, bit error rate, and device reliability.

Innovation Solution

A SHAMR scheme with two SHE layers separated by an insulation layer in the write gap, where a first current is applied between the main pole and the first SHE layer, and a second current is applied between the trailing shield and the second SHE layer, using positive or negative giant Spin Hall Angle materials to generate transverse spin transfer torque, enhancing the write and return fields without a current density threshold and reducing layer protrusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a current is applied across each SHE layer and synchronized with a write current in existing SHAMR designs, then the write field is enhanced, but the device complexity increases due to synchronization requirements and the number of fabrication steps increases

Engineering Contradiction:

Improvewrite field enhancementVSAvoidsynchronization requirements

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent divides the single SHE layer into two separate SHE layers (SHE1 and SHE2) positioned at different locations in the write gap. This segmentation allows each layer to be independently controlled by separate currents (I1 and I2), eliminating the need for complex synchronization with the write current while still achieving enhanced write field through the combined effect of both layers

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an insulation layer as an intermediary between SHE1 and SHE2, which simplifies the electrical configuration by allowing independent current paths through each SHE layer without requiring complex synchronization circuitry. The insulation layer mediates the electrical isolation while maintaining magnetic interaction

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If the write head size is shrunk to increase data areal density, then the storage capacity is improved, but the writability degrades

Engineering Contradiction:

Improvedata areal densityVSAvoidwritability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the magnetic parameters by introducing two SHE layers with giant Spin Hall Angle materials that generate transverse spin transfer torque. This modifies the effective magnetic field and magnetization dynamics in the write gap, enabling enhanced writability even as the write head dimensions are reduced to increase areal density

Inventive Principle:

Principle #35Parameter changes

3Power

If the write gap thickness is reduced to improve writing performance, then the write field concentration is improved, but the reliability concerns increase due to limited thickness

Engineering Contradiction:

Improvewrite field concentrationVSAvoidwrite gap thickness

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent applies local quality by positioning SHE1 and SHE2 at specific locations within the write gap (SHE1 near the main pole, SHE2 near the trailing shield) rather than uniformly distributing the magnetic assistance. This localized placement optimizes the write field concentration at critical regions while maintaining reliable gap thickness

Inventive Principle:

Principle #3Local quality

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 approach improves overwrite, bit error rate, and transition sharpness while reducing the number of fabrication steps and eliminating the need for synchronization, ensuring compatibility with varying write gap thicknesses and preventing SHE layer protrusion during the write process.

Implementation Method 1

transverse spin transfer torque generated by spin polarized I1 in SHE1

Methodology Applied

Scientific EffectSpin Hall Effect: Hall Effect

Implementation Method 2

spin polarized I1 in SHE1 causes a local MP magnetization at the MP/SHE1 interface to enhance a write field

Methodology Applied

Scientific EffectSpin transfer torque:

Implementation Method 3

transverse spin transfer torque generated by spin polarized I2 in SHE2

Methodology Applied

Scientific EffectSpin Hall Effect: Hall Effect

Implementation Method 4

spin polarized I2 in SHE2 causes a local TS magnetization at the SHE2/TS interface to tilt and enhance a return field

Methodology Applied

Scientific EffectSpin transfer torque:

Data Source

PatentUS10714136B1Alternative designs for magnetic recording assisted by two spin hall effect (SHE) layers in the write gap

Publication Date: 2020.07.14 HEADWAY TECHNOLOGIES INC

AI summary

A Spin Hall Effect (SHE) assisted magnetic recording device is disclosed wherein a stack of two SHE layers with an intermediate insulation layer is formed between a main pole (MP) trailing side and trailing shield (TS) bottom surface. Both SHE layers are a Spin Hall Angle (SHA) material with an absolute value for SHA>0.05 and each have front sides at the air bearing surface (ABS) or recessed therefrom. One current (I1) is applied between the MP trailing side and the first SHE layer and is spin polarized to generate spin transfer torque that tilts a local MP magnetization to a direction that enhances a MP write field. Second current (I2) is applied between the second SHE layer and TS and is spin polarized to generate spin transfer torque that tilts a local TS magnetization to a direction that increases the TS return field and improves bit error rate.