Perpendicular Magnetic Recording Head Trailing Gap Design
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Solution Overview
Problem
Conventional perpendicular magnetic recording heads with side shields face a trade-off between maintaining the magnitude of the recording magnetic field and suppressing its spread, making it difficult to optimize recording performance.
Innovation Solution
The design includes a magnetic pole with side shields and a trailing shield, where the trailing gap has distinct regional parts with varying thicknesses, allowing for effective absorption of magnetic flux spread components near the trailing edge, thereby minimizing excessive absorption and maintaining field magnitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If side shields are provided on both sides of the magnetic pole to suppress the spread of the perpendicular magnetic field, then the spread of the magnetic field is reduced, but the magnitude of the recording magnetic field decreases
Solution Approach 1:
The trailing gap is designed with non-uniform thickness, having a first regional part with smaller thickness near the magnetic pole and a second regional part with larger thickness farther from the pole. This local variation in gap thickness creates zones with different magnetic flux absorption characteristics, allowing the trailing shield to selectively absorb spread components while preserving the main field magnitude.
Solution Approach 2:
The trailing gap is segmented into distinct regional parts (first and second regional parts) with different thicknesses. This segmentation allows different portions of the trailing gap to perform different functions: the first regional part maintains field strength while the second regional part absorbs spread flux components.
2Manufacturing precision
If the trailing gap has uniform thickness to simplify manufacturing, then manufacturing precision is improved, but recording performance deteriorates due to excessive absorption of magnetic flux
Solution Approach 1:
Rather than maintaining uniform thickness throughout, the trailing gap intentionally introduces local quality variations with different thickness regions. This resolves the contradiction by showing that controlled non-uniformity improves recording performance while remaining manufacturable through standard thin-film deposition techniques.
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 enables both the enhancement of recording magnetic field strength and reduction of its spread, leading to improved recording performance and reduced adjacent track erase, with increased track and linear recording densities.
Implementation Method 1
This makes it easier for a spread component of magnetic flux to be absorbed in a portion in the vicinity of the trailing edge in the side shield
Implementation Method 2
a thin-film coil for generating magnetic flux and a main magnetic-pole layer which leads the magnetic flux generated in the thin-film coil to a recording medium
Implementation Method 3
a perpendicular magnetic recording method in which the direction of the signal magnetic field is set to the direction intersecting a plane of the recording medium
Data Source
AI summary
A perpendicular magnetic write head includes: a magnetic pole; a pair of side shields on both sides, in a write-track width direction, of the magnetic pole with respective side gaps in between; a trailing shield on a trailing side of the magnetic pole and the pair of side shields with a trailing gap in between. Each of the magnetic pole, the side shield, the trailing shield, the side gap, and the trailing gap has an end face exposed on an air bearing surface. The trailing gap has a first regional part and a second regional part. The first regional part separates a trailing edge of the magnetic pole from the trailing shield, and the second regional part separates the pair of side shields from the trailing shield. All or a part of the second regional part has a thickness larger than a thickness of the first regional part.