Perpendicular Magnetic Recording Head Side Fringing Suppression

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Solution Overview

Problem

Conventional perpendicular magnetic recording heads face challenges in suppressing side fringing while maintaining recording magnetic field intensity, as existing magnetic shield layers either absorb recording magnetic fluxes or fail to provide sufficient side fringing suppression.

Innovation Solution

A perpendicular magnetic recording head design featuring a main magnetic pole layer and return yoke layer with a magnetic gap layer, and a pair of side shield layers separated by a first and second gap layer, where the second gap layer is thinner than the first, allowing for controlled absorption of side magnetic fluxes and maintenance of recording magnetic field intensity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a magnetic shield layer is provided to surround the main magnetic pole layer, then side fringing is suppressed, but recording magnetic field intensity decreases

Engineering Contradiction:

Improveside fringingVSAvoidrecording magnetic field intensity

Core Design Contradiction:

Object-affected harmful factorsVSForce

Solution Approach 1:

The magnetic gap layer is divided into two distinct layers: a first gap layer between the main magnetic pole layer and side shield layers, and a second gap layer between the return yoke layer and side shield layers. This segmentation allows different magnetic flux control in different regions, enabling side fringing suppression while preserving recording magnetic field intensity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first gap layer and second gap layer have different thicknesses, creating local variations in magnetic reluctance. The thinner second gap layer allows stronger leakage magnetic fields that enhance side fringing suppression, while the first gap layer maintains appropriate magnetic coupling for recording field intensity.

Inventive Principle:

Principle #3Local quality

2Force

If a pair of magnetic shield layers are provided with a large gap therebetween, then recording magnetic field intensity is maintained, but side fringing suppression becomes insufficient

Engineering Contradiction:

Improverecording magnetic field intensityVSAvoidside fringing

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The gap between side shield layers and return yoke layer is controlled by adjusting the thickness of the second gap layer. By optimizing this parameter, the magnetic shield layers can effectively suppress side fringing while maintaining sufficient recording magnetic field intensity through the first gap layer.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the track width is narrowed for higher recording density, then recording density improves, but side fringing suppression becomes more difficult

Engineering Contradiction:

Improverecording densityVSAvoidside fringing

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The magnetic gap layers act as intermediaries that mediate between the main magnetic pole layer and side shield layers. They provide controlled magnetic coupling that allows side fringing suppression even in narrow track configurations, enabling higher recording densities without sacrificing field integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 suppresses side fringing while preserving the recording magnetic field intensity, allowing for narrower track widths and improved recording performance by adjusting the gap layer thicknesses to optimize magnetic flux absorption.

Implementation Method 1

a magnetic gap layer interposed between the main magnetic pole layer and return yoke layer on the medium-opposing surface side

Methodology Applied

Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 2

The second gap layer is thinner than the first gap layer and thus causes a stronger leakage magnetic field between the return yoke layer and the pair of side shield layers

Methodology Applied

Scientific EffectMagnetic reluctance: Magnetic Reluctance

Implementation Method 3

a pair of side shield layers positioned on both sides in a track width direction of the main magnetic pole layer... so that leakage magnetic fields are easier to occur... side magnetic fluxes leaking from the main magnetic pole layer are easier to be absorbed by the pair of side shield layers

Methodology Applied

Scientific EffectMagnetic shielding: Magnetic Field

Implementation Method 4

a coil layer inducing a recording magnetic field between the main magnetic pole layer and return yoke layer upon energization

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS8054578B2Perpendicular magnetic recording head that suppresses side fringing

Publication Date: 2011.11.08 TDK CORP

AI summary

A perpendicular magnetic recording head includes a main magnetic pole layer and a return yoke layer which are laminated with a magnetic gap layer interposed therebetween on a medium-opposing surface, and a pair of side shield layers positioned on both sides in the track width direction of the main magnetic pole layer while interposing a nonmagnetic material layer therebetween. The magnetic gap layer is constituted by a first gap layer formed in a partial area in the track width direction bridging the main magnetic pole layer and the pair of side shield layers, and a second gap layer thinner than the first gap layer and interposed between the return yoke layer and the pair of side shield layers in a remaining area where the first gap layer is absent.