Dual Spin Hall Layer MAMR Write Head

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Solution Overview

Problem

MAMR write heads based on spin-orbital torque (SOT) suffer from degradation due to uni-directional ampere magnetic fields, which reduces the reliability of the spin torque layer.

Innovation Solution

Incorporating dual spin Hall layers with opposite spin Hall angles or a single spin Hall layer wrapped around the spin torque layer to generate balanced or multiple ampere magnetic fields, reducing degradation by applying forces in opposite directions or increasing the number of charge current paths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single spin Hall layer is used to generate spin orbital torque, then the structure is simple, but the spin torque layer degrades due to uni-directional ampere magnetic fields

Engineering Contradiction:

Improvestructure simplicityVSAvoidspin torque layer reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The single spin Hall layer is segmented into dual spin Hall layers with opposite spin Hall angles, allowing the ampere magnetic fields to act in opposite directions and reduce degradation of the spin torque layer

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The dual spin Hall layers generate counteracting ampere magnetic fields that balance each other's harmful effects on the spin torque layer, similar to counterweight principles where opposing forces neutralize degradation

Inventive Principle:

Principle #8Anti-weight (Counterweight)

2Reliability

If dual spin Hall layers with opposite spin Hall angles are used, then the spin torque layer degradation is reduced, but the device complexity increases

Engineering Contradiction:

Improvespin torque layer reliabilityVSAvoidspin Hall layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The dual spin Hall layers are designed with opposite spin Hall angles (asymmetric properties) to generate ampere magnetic fields in opposite directions, which counterbalance the degradation effects while maintaining functional symmetry in performance

Inventive Principle:

Principle #4Asymmetry

3Reliability

If a wrap around spin Hall layer is used to produce multiple ampere magnetic fields, then the spin torque layer degradation is reduced, but the manufacturing complexity increases

Engineering Contradiction:

Improvespin torque layer reliabilityVSAvoidmanufacturing ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The spin Hall layer is configured to wrap around the spin torque layer in a three-dimensional arrangement, producing multiple ampere magnetic fields from different directions. This dimensional change allows multiple protective fields without adding multiple separate layers, simplifying manufacturing compared to planar multi-layer approaches

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 balanced or multiple ampere magnetic fields effectively reduce the degradation of the spin torque layer, enhancing the reliability and performance of the MAMR write head.

Implementation Method 1

charge current through a spin Hall layer generates a spin current in the spin Hall layer. The spin currents from the spin Hall layer exert a spin orbital torque that causes the magnetization of a spin torque layer (STL) to switch or precession

Methodology Applied

Scientific EffectSpin Hall Effect: Hall Effect

Implementation Method 2

Precession of the magnetization of the STL generates an AC assisting field or a DC assisting field to the write field

Methodology Applied

Scientific EffectMicrowave assisted magnetic recording:

Implementation Method 3

the charge current through the spin Hall layer produces an ampere magnetic field 80. The ampere magnetic field 80 which acts on the ferromagnetic STL 71 and degrades the ferromagnetic STL 71 over time

Methodology Applied

Scientific EffectAmpere magnetic field: Ampère's Circuital Law

Data Source

PatentUS11170804B2Spin orbital torque based microwave assisted magnetic recording with dual spin hall layers or wrap around spin hall layer

Publication Date: 2021.11.09 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

A magnetic recording head includes a trailing shield and a main pole. A trailing shield gap is between the trailing shield and the main pole. A spin orbital torque structure is within the trailing shield gap. The spin orbital torque structure includes a spin torque layer having a first side and a second side at a media facing surface. A first spin Hall layer is along the first side of the spin torque layer. A second spin Hall layer is along the second side of the spin torque layer. The first spin Hall layer comprises a heavy metal material having a positive spin Hall angle. The second spin Hall layer comprises a heavy metal material having a negative spin Hall angle.