Perpendicular Magnetic Write Head Shield Magnetization Control
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Solution Overview
Problem
High recording densities in magnetic recording devices lead to heat fluctuation issues, causing leakage magnetic fields and far track interference (FTI), which deteriorate data quality and make it difficult to maintain non-volatility, especially as data is rewritten multiple times.
Innovation Solution
A perpendicular magnetic recording head with thin and thick shield regions of varying coercive forces, where the thin shield region surrounds the main pole and the thick shield region partially surrounds the thin shield region, allowing for controlled magnetization direction to reduce FTI by adjusting film thickness and material composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the distance between the magnetic recording head and recording medium is reduced to generate a strong magnetic field, then recording magnetic field strength is improved, but leakage magnetic field increases causing far track interference
Solution Approach 1:
The shield is divided into multiple regions with different thicknesses: a first shield region with first thickness and a second shield region with second thickness greater than the first. This segmentation allows different parts of the shield to perform different functions - the thinner first region reduces leakage magnetic field to eliminate far track interference, while the thicker second region maintains strong magnetic field generation for recording, thus resolving the contradiction between reducing leakage and maintaining recording field strength.
2Power
If a flare structure is provided on the main pole to generate strong magnetic field, then recording magnetic field strength is improved, but magnetic flux leaks directly from the flare part to the recording medium
Solution Approach 1:
The shield acts as an intermediary structure between the main pole with flare and the recording medium. The shield intercepts and redirects magnetic flux that would otherwise leak directly from the flare portion to the medium. By positioning the shield adjacent to the main pole and configuring it with varying thickness, the magnetic flux is channeled through the shield rather than leaking outward, thus preventing far track interference while preserving the strong field generation capability of the flare structure.
3Object-generated harmful factors
If shielding structures are added to reduce leakage magnetic field, then far track interference is reduced, but device complexity increases
Solution Approach 1:
Instead of making the entire shield uniformly thick, the invention applies local quality by varying the shield thickness in different regions. The first shield region has a thinner first thickness where leakage control is critical, while the second shield region has a thicker second thickness where structural support and additional shielding are beneficial. This localized differentiation optimizes the balance between reducing far track interference and minimizing overall device complexity.
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 restricts FTI, maintaining data quality and non-volatility by controlling the magnetization direction of the shield layers, reducing leakage magnetic fields and ensuring reliable data retention even after multiple rewrites.
Implementation Method 1
at least one thin shield region having a high coercive force and a magnetization direction oriented towards the right when viewed from the MFS with the leading side on bottom and the trailing side on top, and at least one thick shield region having a low coercive force
Implementation Method 2
The thin shield region has a higher coercive force than the thick shield region
Data Source
AI summary
Embodiments disclosed herein generally relate to a perpendicular magnetic recording head for recording magnetic information and a magnetic recording device employing the magnetic head. The magnetic recording head comprises at least one thin shield region having a high coercive force and a magnetization direction oriented towards the right when viewed from the MFS with the leading side on bottom and the trailing side on top, and at least one thick shield region having a low coercive force. The thin shield region surrounds a main pole, and the thick shield region partially surrounds the thin shield region. The magnetic recording head is able to reduce FTI by controlling the magnetization direction of the shield layers.