Magnetic Head Main Pole and Shield Gap Design
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Solution Overview
Problem
Conventional magnetic heads for perpendicular magnetic recording face challenges in preventing skew-induced adjacent track erasure while maintaining improved write characteristics without compromising the function of the write shield, as inclined portions and surfaces can lead to magnetic flux leakage and saturation issues.
Innovation Solution
The magnetic head design includes a main pole with inclined portions and a write shield featuring inclined surfaces, with a gap part made of nonmagnetic material interposed between them, allowing for controlled magnetic flux direction and prevention of flux leakage, thereby enhancing write characteristics without compromising the write shield's function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the main pole is configured with inclined portions and the write shield with inclined surfaces to prevent skew-induced adjacent track erasure, then recording density and write characteristics are improved, but magnetic flux leakage occurs causing overwrite property degradation
Solution Approach 1:
A gap part made of nonmagnetic material is introduced between the main pole and write shield to prevent direct magnetic flux leakage while maintaining the inclined configuration for skew compensation. The nonmagnetic gap part acts as an intermediary that blocks the harmful magnetic flux path without interfering with the beneficial inclined geometry for preventing adjacent track erasure.
Solution Approach 2:
The magnetic head structure implements different geometries at different locations: the main pole has inclined portions at its end face while the write shield has inclined surfaces, and a nonmagnetic gap part is positioned specifically between them. This local differentiation allows the inclined portions to prevent skew-induced erasure while the gap part locally blocks magnetic flux leakage.
2Manufacturing precision
If the main pole thickness is reduced near the medium facing surface to prevent adjacent track erasure, then recording density is improved, but overwrite property deteriorates due to insufficient magnetic flux direction capability
Solution Approach 1:
The main pole is designed with varying thickness: thinner near the medium facing surface to prevent adjacent track erasure and improve recording density, and thicker at other portions to maintain sufficient magnetic flux direction capability for good overwrite property. This local quality variation resolves the contradiction between recording density and overwrite performance.
3Object-generated harmful factors
If the write shield volume is reduced to minimize magnetic flux saturation, then flux leakage is decreased, but the write shield function is compromised
Solution Approach 1:
The nonmagnetic gap part serves as an intermediary that blocks magnetic flux leakage paths without requiring a large write shield volume. This allows the write shield to maintain sufficient volume for its protective function while the gap part prevents flux leakage and saturation issues.
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 prevents skew-induced adjacent track erasure and improves write characteristics by managing magnetic flux, ensuring high recording density and accurate data writing without data loss due to magnetic flux saturation.
Implementation Method 1
a coil that produces a magnetic field corresponding to data to be written on a recording medium
Implementation Method 2
a main pole that allows a magnetic flux corresponding to the magnetic field produced by the coil to pass, and produces a write magnetic field for writing the data on the recording medium
Data Source
AI summary
A magnetic head with a main pole is provided. The main pole has a bottom end including an inclined portion. A write shield has a first inclined surface opposed to the inclined portion and a second inclined surface that is located farther from a medium facing surface than is the first inclined surface. The first inclined surface has a first end located in the medium facing surface and a second end opposite thereto. The second inclined surface has a third end connected to the second end and a fourth end opposite thereto. The second inclined surface forms a greater angle than does the first inclined surface relative to a direction perpendicular to the medium facing surface. The distance between the main pole and an arbitrary point on the second inclined surface increases with decreasing distance between the arbitrary point and the fourth end.