Perpendicular Magnetic Write Head Flux Leakage Suppression

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Perpendicular magnetic write heads face challenges in optimizing the magnetic domain structure of main component elements, leading to unintended erasure of information due to leakage of magnetic flux from the main magnetic pole layer at non-writing times.

Innovation Solution

A perpendicular magnetic write head is designed with a main magnetic pole layer having a specified internal stress, an auxiliary magnetic pole layer recessed from the main pole layer, and a nonmagnetic layer with the same internal stress direction as the main magnetic pole layer, optimizing the magnetic domain structures to prevent flux leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the auxiliary magnetic pole layer is disposed on the trailing side of the main magnetic pole layer to suppress unintended erasure, then information retention is improved, but the magnetic domain structure optimization is insufficient leading to flux leakage

Engineering Contradiction:

Improveinformation retentionVSAvoidflux leakage

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The patent applies local quality by introducing a nonmagnetic layer with specific internal stress characteristics in a localized region between the auxiliary magnetic pole layer and the main magnetic pole layer. This nonmagnetic layer has internal stress in the same direction as the main magnetic pole layer, creating a localized stress field that optimizes the magnetic domain structure specifically in the flux transmission path, thereby preventing flux leakage while maintaining information retention.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by carefully controlling the internal stress parameters of the nonmagnetic layer, ensuring its internal stress direction matches that of the main magnetic pole layer. This parameter optimization modifies the magnetic domain structure in the critical region, transforming the magnetic flux distribution to prevent unintended erasure while maintaining reliable information storage.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the magnetic domain structure is optimized to prevent flux leakage, then unintended erasure is suppressed, but the structural complexity increases due to additional layers

Engineering Contradiction:

Improvedata retentionVSAvoidlayer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The nonmagnetic layer is strategically positioned only in the specific region where flux leakage occurs, between the auxiliary and main magnetic pole layers. This localized approach allows the patent to optimize magnetic domain structure precisely where needed without adding complexity throughout the entire head structure, maintaining simplicity in non-critical areas.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The nonmagnetic layer acts as an intermediary element that mediates between the auxiliary magnetic pole layer and the main magnetic pole layer. It provides the necessary stress field to optimize magnetic domain structure without being a magnetic layer itself, thus achieving flux leakage prevention through a non-magnetic mechanism that simplifies the overall magnetic circuit design.

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 configuration effectively suppresses unintended erasure of information by maintaining the magnetic domain structures in a good state, ensuring that magnetic flux is not leaked out after information-writing, thereby enhancing data retention.

Implementation Method 1

a main magnetic pole layer which leads magnetic flux to a write medium

Methodology Applied

Scientific EffectMagnetism: Magnetism

Implementation Method 2

optimizing the magnetic domain structures to prevent flux leakage

Methodology Applied

Scientific EffectMagnetoelasticity: Magnetoelastic Effects

Data Source

PatentUS7808743B2Perpendicular magnetic write head having a structure that suppresses unintended erasure of information on a write medium at a non-writing time

Publication Date: 2010.10.05 TDK CORP

AI summary

A perpendicular magnetic write head includes an auxiliary magnetic pole layer disposed on a trailing or leading side of a main magnetic pole layer, the auxiliary magnetic pole layer being recessed from the main magnetic pole layer. A nonmagnetic layer is disposed in a layer same as the auxiliary magnetic pole layer and in front of the auxiliary magnetic pole layer, the nonmagnetic layer having an internal stress of a direction same as that of the main magnetic pole layer, and a write shield layer is disposed in a layer same as the auxiliary magnetic pole layer and in front of the auxiliary magnetic pole layer, the write shield layer being separated from the main magnetic pole layer with a gap layer in between. The nonmagnetic layer is arranged to fill up a space between the auxiliary magnetic pole layer and the write shield layer.