Magnetic Head Gap Section Design for Flux Leakage Control
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording systems face challenges in maintaining write characteristics without compromising the function of the write shield, as existing designs either suffer from flux leakage or inadequate magnetic field strength due to the thickness of the gap sections, leading to unwanted erasure and reduced recording density.
Innovation Solution
The magnetic head incorporates a gap section with nonmagnetic layers to optimize the distance between the main pole and the write shield, reducing flux leakage while maintaining the desired distance for effective magnetic field generation, achieved through a specific configuration of nonmagnetic layers and shield geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a wrap-around shield is provided to prevent unwanted erasure, then adjacent track erasure is reduced, but write characteristics are degraded due to flux leakage to the shield
Solution Approach 1:
A nonmagnetic gap section is introduced as an intermediary between the main pole and the wrap-around shield. This gap section prevents direct magnetic coupling, thereby reducing flux leakage from the main pole to the shield while maintaining the shield's protective function against adjacent track erasure.
Solution Approach 2:
The gap section is divided into multiple segments positioned at different locations (leading end, side surfaces, trailing end) around the main pole. This segmented approach allows optimized control of magnetic flux paths at different positions, reducing overall flux leakage to the shield while preserving write field strength.
2Loss of energy
If the gap section between main pole and write shield is made thinner, then flux leakage is reduced, but the write magnetic field strength is weakened
Solution Approach 1:
The gap section thickness is optimized differently at different locations: thinner at the leading end to reduce flux leakage, and appropriately thicker at the trailing end to maintain write field strength. This local optimization resolves the contradiction between reducing flux leakage and maintaining write field strength.
3Strength
If the gap section is made thicker, then write magnetic field strength is maintained, but unwanted erasure increases due to compromised write shield function
Solution Approach 1:
The gap section is segmented into multiple positions around the main pole, allowing different thickness optimizations at each location. The shield is also segmented into leading, side, and trailing portions, each with optimized gap thickness to balance write field strength maintenance with unwanted erasure prevention.
4Object-affected harmful factors
If a wrap-around shield is provided to prevent unwanted erasure, then wide-area track erasure is reduced, but device complexity increases
Solution Approach 1:
The wrap-around shield serves multiple functions: preventing both adjacent track erasure and wide-area track erasure, while the segmented gap section provides both flux leakage reduction and write field strength optimization. This multi-functionality justifies the increased structural 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 enhances write characteristics by reducing unwanted erasure and improving recording density without compromising the function of the write shield, allowing for precise control of the write magnetic field and better performance in perpendicular magnetic recording systems.
Implementation Method 1
a coil, a main pole The coil produces a magnetic field corresponding to data to be written on the recording medium
Implementation Method 2
The main pole passes a magnetic flux corresponding to the magnetic field produced by the coil, and produces a write magnetic field for use to write data on the recording medium
Implementation Method 3
The wrap-around shield has the function of capturing a magnetic flux that is produced from the end face of the main pole and spreads in directions other than the direction perpendicular to the plane of the recording medium
Data Source
AI summary
A magnetic head includes a main pole, a write shield and a gap section. The write shield includes a leading shield having a top surface opposed to a bottom end of the main pole. The gap section includes a leading gap section for separating the leading shield from the bottom end of the main pole. The leading gap section is formed using a first nonmagnetic layer and a second nonmagnetic layer. The first nonmagnetic layer has a first front end located closest to but at a distance from the medium facing surface. The second nonmagnetic layer has a second front end located in the medium facing surface.