Perpendicular Magnetic Recording Head Recess Shield Design
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Solution Overview
Problem
Current perpendicular magnetic recording heads face challenges in achieving higher surface recording density while suppressing wide adjacent track erase (WATE) effects, which can lead to incorrect writing in adjacent tracks, and often result in complex manufacturing processes and degradation of magnetization efficiency.
Innovation Solution
A perpendicular magnetic recording head design featuring a magnetic pole with an end surface exposed on the air bearing surface, a leading shield, a leading gap, and a recess shield positioned opposite to the magnetic pole with its mid-part distanced from the leading shield in the track width direction and in contact at other parts, allowing for suppression of magnetic flux return and WATE effects without lengthening the magnetic path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield is provided to surround the main magnetic pole or a magnetic circuit is provided on both trailing and leading sides, then WATE suppression is improved, but device complexity increases
Solution Approach 1:
The invention extracts the leading shield from the air bearing surface, recessing it into the substrate. This removes the problematic exposed leading shield that causes complex manufacturing while retaining the essential WATE suppression function through the recessed configuration and magnetic circuit design.
Solution Approach 2:
The invention transitions the leading shield from a surface-level component to a recessed component by moving it into the substrate depth dimension. This vertical relocation simplifies the air bearing surface geometry and manufacturing while maintaining the shield's magnetic flux containment function.
2Object-affected harmful factors
If part of the leading shield is recessed from the air bearing surface, then WATE suppression is improved, but the length of the magnetic path increases causing degradation in magnetization efficiency
Solution Approach 1:
The invention applies different configurations to different parts of the shield structure. The leading shield is recessed while the trailing shield remains at the air bearing surface, creating localized magnetic path optimization that suppresses WATE where needed while maintaining efficient magnetization where critical.
Solution Approach 2:
The invention introduces a magnetic circuit layer in the substrate that acts as an intermediary, providing a low-reluctance path for magnetic flux. This mediator enables the recessed leading shield configuration to suppress WATE without forcing the magnetic flux to travel through long air gaps, thereby preserving magnetization efficiency.
3Object-affected harmful factors
If a magnetic circuit exists on the leading side, then WATE suppression is improved, but recording performance deteriorates due to magnetic flux returning to the leading shield
Solution Approach 1:
Instead of placing the magnetic circuit material directly at the air bearing surface on the leading side, the invention inverts the approach by recessing the leading shield into the substrate and positioning the magnetic circuit layer beneath it. This inverted configuration prevents magnetic flux from returning to the leading shield while maintaining WATE suppression.
Solution Approach 2:
The invention nests the recessed leading shield within the substrate, placing it inside the magnetic circuit layer. This nested configuration allows the magnetic circuit to surround and contain the leading shield, preventing magnetic flux leakage and return paths that would degrade recording performance while maintaining WATE suppression.
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 magnetic flux return and WATE occurrences, enabling higher density recording while preventing incorrect writing to adjacent tracks and simplifying the manufacturing process.
Implementation Method 1
a main magnetic pole that guides a magnetic flux generated in a thin film coil to a recording medium
Implementation Method 2
a leading shield including an end surface exposed on the air bearing surface... a recess shield including a mid-part and other parts, and provided at a position on a side opposite to the magnetic pole with the leading shield in between
Data Source
AI summary
The perpendicular magnetic recording head includes: a magnetic pole including an end surface exposed on an air bearing surface, and extending in a height direction perpendicular to the air bearing surface; a leading shield including an end surface exposed on the air bearing surface; a leading gap provided between the magnetic pole and the leading shield; and a recess shield including a mid-part and other parts, and provided at a position on a side opposite to the magnetic pole with the leading shield in between, the mid-part being distanced from the leading shield in a track width direction, the other parts being in contact with the leading shield, and the position being recessed from the air bearing surface.