Spin-orbit torque magnetic recording head with spin Hall structure

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current magnetic recording methods, such as those using pseudo spin-valve structures, face challenges with high switching current and voltage requirements, leading to lower energy efficiency in magnetic media devices like hard disk drives.

Innovation Solution

A magnetic recording head design incorporating a spin-torque structure surrounded by a spin Hall structure generates strong spin-orbit torque, which enforces in-plane magnetization oscillation and reduces the current needed for operation, utilizing a main pole and side shields with a spin Hall structure to enhance energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If pseudo spin-valve structure is used for magnetic recording, then magnetization switching can be induced, but high switching current and voltage are required leading to lower energy efficiency

Engineering Contradiction:

Improveenergy efficiencyVSAvoidswitching current and voltage

Core Design Contradiction:

Use of energy by stationary objectVSPower

Solution Approach 1:

The patent changes the fundamental operating parameters by transitioning from spin-transfer torque (STT) to spin-orbit torque (SOT) mechanism. This involves changing the material composition to include heavy metal layers (Pt, Pd, Ir) with high spin-orbit coupling, and modifying the magnetic layer structure to CoFeB with perpendicular magnetic anisotropy. These parameter changes enable magnetization switching at lower current densities, directly improving energy efficiency while reducing switching power requirements

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the spin-transfer torque mechanism with a spin-orbit torque mechanism. Instead of using spin-polarized current flowing through the magnetic tunnel junction to induce precession, the invention uses spin current generated from spin Hall effect or Rashba effect in heavy metal layers. This mechanical substitution of the torque generation mechanism achieves more efficient energy conversion and lower switching currents

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If pseudo spin-valve structure is used, then magnetization switching is achieved, but the structure is difficult to manufacture

Engineering Contradiction:

Improvemanufacturing easeVSAvoidstructure complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent segments the magnetic recording head into distinct functional layers: heavy metal layer (Pt/Pd/Ir), CoFeB magnetic layer, Ru spacer layer, and Ta capping layer. Each layer has a specific thickness and material composition optimized for its function. This segmentation allows for standardized fabrication processes for each layer type and simplifies the overall manufacturing by enabling modular assembly and testing of individual components

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite material structures combining heavy metals (Pt, Pd, Ir) with high spin-orbit coupling, CoFeB with perpendicular magnetic anisotropy, and Ru/Ta spacer layers. These composite materials provide synergistic effects where each material contributes specific properties: heavy metals generate spin-orbit torque, CoFeB provides stable perpendicular magnetization, and Ru/Ta layers provide structural stability and magnetic decoupling. The composite structure achieves superior performance while maintaining manufacturability through established thin-film deposition techniques

Inventive Principle:

Principle #40Composite materials

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 solution achieves higher energy efficiency by reducing critical switching current density and improving reliability through increased effective spin injection efficiency, resulting in improved data storage performance.

Implementation Method 1

a spin Hall structure disposed at the media facing surface... Strong spin-orbit torque (SOT) is generated from the spin Hall structure

Methodology Applied

Scientific EffectSpin Hall Effect: Hall Effect

Implementation Method 2

Strong spin-orbit torque (SOT) is generated from the spin Hall structure, enforcing in-plane magnetization oscillation in the spin-torque structure

Methodology Applied

Scientific EffectSpin-orbit torque:

Implementation Method 3

microwave assisted magnetic recording (MAMR) utilizes spin-transfer torque (STT), which is generated from a pseudo spin-valve structure. During operation, electrical current flows from the main pole to the trailing shield hot seed layer, and the spin-torque layer magnetization switching (or precession) is induced by the STT

Methodology Applied

Scientific EffectSpin transfer torque:

Data Source

PatentUS10014012B1Spin-orbit torque based magnetic recording

Publication Date: 2018.07.03 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

The present disclosure generally relates to data storage devices, and more specifically, to a magnetic media drive employing a magnetic recording head. The head includes a main pole, a spin-torque structure surrounding at least a portion of the main pole at a media facing surface (MFS), and a spin Hall structure surrounding the spin-torque structure. Strong spin-orbit torque (SOT) is generated from the spin Hall structure, enforcing in-plane magnetization oscillation in the spin-torque structure. The SOT based head with the spin Hall structure surrounding the spin-torque structure utilizes less current flowed to the spin Hall structure due to the strong SOT generated by the spin Hall structure.