Magnetic Sensor Recessed AFM Pinning for Data Density

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The need to decrease gap spacing in magnetic data recording sensors to increase data density while maintaining robust sensor performance and stability is unmet due to limitations in reducing sensor layer thickness without adverse effects on performance.

Innovation Solution

A magnetoresistive sensor design with an antiferromagnetic pinning layer embedded within a bottom shield, where the antiferromagnetic layer is exchange coupled with the pinned layer structure and does not contribute to the read gap, allowing for reduced gap spacing and enhanced data density without compromising sensor stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the sensor layers are made thinner to reduce gap spacing, then data density increases, but sensor performance and stability deteriorate

Engineering Contradiction:

Improvedata densityVSAvoidsensor performance and stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent relocates the antiferromagnetic pinning layer from the vertical stack between shields to a horizontal embedding within the bottom shield structure. This dimensional repositioning allows the pinning layer to provide magnetic stabilization without contributing to the vertical gap measurement, effectively decoupling the gap spacing from the pinning layer thickness and enabling thinner sensor layers without compromising stability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The antiferromagnetic pinning layer is nested within the bottom shield structure, specifically embedded in the magnetic shield base layer. This nesting arrangement integrates the pinning function into the shield itself, allowing the pinning layer to be positioned outside the active sensor gap region while maintaining its magnetic coupling function with the pinned layer structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Productivity

If the gap spacing is reduced to increase data density, then linear data density improves, but sensor performance deteriorates

Engineering Contradiction:

Improvelinear data densityVSAvoidsensor performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent extracts the antiferromagnetic pinning layer from the active sensor gap region and relocates it to the bottom shield structure. This extraction removes the pinning layer's contribution to the read gap measurement, allowing the gap spacing to be minimized for higher data density while the pinning layer continues to provide necessary magnetic stabilization through exchange coupling with the pinned layer structure.

Inventive Principle:

Principle #2Taking out (Extraction)

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 design effectively increases data density by reducing the read gap while maintaining robust magnetic pinning and sensor performance, achieving improved data storage capabilities.

Implementation Method 1

a layer of anti-ferromagnetic material embedded in the first magnetic shield and exchange coupled with a portion of the pinned layer structure

Methodology Applied

Scientific EffectExchange coupling:

Implementation Method 2

A magnetoresistive sensor such as a Giant Magnetoresistive (GMR) sensor

Methodology Applied

Scientific EffectGiant magnetoresistive effect:

Implementation Method 3

or a Tunnel Junction Magnetoresistive (TMR) sensor

Methodology Applied

Scientific EffectTunnel magnetoresistive effect:

Data Source

PatentUS9042062B2Magnetic sensor with recessed AFM shape enhanced pinning and soft magnetic bias

Publication Date: 2015.05.26 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

A magnetic read sensor having an antiferromagnetic located embedded within a magnetic shield of the sensor so that the antiferromagnetic layer can pin the magnetization of the pinned layer without contributing to read gap thickness. The sensor is configured with a pinned layer having a free layer structure located within an active area of the sensor and a pinned layer that extends beyond the free layer and active area of the sensor. The antiferromagnetic layer can be located outside of the active and exchange coupled with the extended portion of the pinned layer.