Magnetic Head Tapered Face Design for Leakage Flux Reduction
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Solution Overview
Problem
Magnetic heads in magnetic recording/reproducing apparatuses face issues with excessive leakage magnetic flux to the trailing shield, leading to magnetic saturation and insufficient magnetic field gradient, which affects bit error rate and recording performance.
Innovation Solution
A magnetic head design featuring a continuous tapered face on the magnetic pole and non-magnetic layers opposed to the trailing shield, minimizing the area of the tapered face and reducing leakage flux, while increasing the volume of the trailing shield to enhance its tolerance for magnetic saturation and improve the magnetic field gradient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the tapered face of the magnetic pole is wholly opposed to the trailing shield to increase the strength of the recording magnetic field, then the recording magnetic field strength is improved, but excessive leakage magnetic flux is generated from the magnetic pole to the trailing shield
Solution Approach 1:
The patent divides the trailing shield structure into multiple segments: a main body portion and a protruding portion extending toward the magnetic pole. This segmentation allows the magnetic flux to be managed in different zones, with the protruding portion specifically positioned to intercept and redirect leakage flux away from the magnetic pole interface, thereby reducing harmful leakage while preserving recording field strength.
Solution Approach 2:
The patent introduces a nonmagnetic layer as an intermediary substance between the magnetic pole and the trailing shield. This nonmagnetic layer acts as a magnetic flux barrier that prevents direct coupling between the magnetic pole and trailing shield, thereby reducing leakage magnetic flux while allowing the recording magnetic field to remain effective in the recording gap region.
2Shape
If the magnetic pole is formed with a tapered face whose inclination angle varies in a stepwise fashion or with a curved face to gently increase the thickness of the magnetic pole layer, then the magnetic pole layer thickness is gently increased, but the area of the magnetic pole opposed to the trailing shield increases causing similar leakage problems
Solution Approach 1:
The trailing shield is segmented into a main body and a protruding portion that extends forward. This segmentation creates a non-uniform opposition area between the magnetic pole and trailing shield, allowing the magnetic pole thickness to be gently increased without proportionally increasing the opposed area, thereby maintaining reduced leakage flux while achieving the desired thickness profile.
Solution Approach 2:
The patent extends the trailing shield in the longitudinal dimension (creating a protruding portion) rather than simply increasing the transverse area of opposition. This dimensional change allows the magnetic pole layer thickness to be increased gently without proportionally increasing the area opposed to the trailing shield, thereby avoiding increased leakage flux.
3Quantity of substance
If a large amount of magnetic flux leaks to the trailing shield, then the trailing shield easily causes magnetic saturation, but the recording magnetic field from the magnetic pole to the magnetic recording medium cannot have a sufficient magnetic field gradient
Solution Approach 1:
The patent extracts or redirects the leakage magnetic flux path by introducing the protruding portion of the trailing shield. This protruding portion intercepts the leakage flux before it can cause saturation of the main trailing shield body, effectively separating the useful recording flux from the harmful leakage flux paths and maintaining sufficient magnetic field gradient for reliable recording.
Solution Approach 2:
The nonmagnetic layer serves as an intermediary that blocks the direct path of magnetic flux from the magnetic pole to the trailing shield. This intermediary prevents excessive flux from reaching the trailing shield and causing saturation, while allowing the recording magnetic field to maintain its gradient through the recording gap to the magnetic recording medium.
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
The design effectively reduces leakage magnetic flux, increases the trailing shield's tolerance for magnetic saturation, and improves the magnetic field gradient, resulting in enhanced bit error rate and recording performance.
Implementation Method 1
a part of the tapered face is formed of the non-magnetic layer, which makes it possible to reduce an area of the tapered face of the magnetic pole layer opposed to the lower side of the trailing shield layer. In addition, since the tapered face extends from the trailing edge of the pole tip at a constant inclination angle, the opposing area of the tapered face can be minimized, unlike the stepwise variation of the inclination angle or the curved face in the above-described prior art. Therefore, it is possible to minimize a leakage magnetic flux from the magnetic pole layer to the trailing shield layer.
Implementation Method 2
If a large amount of magnetic flux leaks to the trailing shield, as described above, the trailing shield easily causes magnetic saturation, so that the recording magnetic field from the magnetic pole to the magnetic recording medium cannot have a sufficient magnetic field gradient.
Data Source
AI summary
The present invention relates to a magnetic head, a manufacturing method therefor, a head assembly, and a magnetic recording/reproducing apparatus. According to the present invention, it includes a magnetic pole layer, a non-magnetic layer, a trailing gap layer, and a trailing shield layer. The magnetic pole layer has a pole tip exposed on a magnetic medium-facing surface. The non-magnetic layer is laid on the magnetic pole layer. The trailing shield layer is exposed on the magnetic medium-facing surface and laid over the magnetic pole layer and the non-magnetic layer with the trailing gap layer between. The magnetic pole layer and the non-magnetic layer have a continuous tapered face opposed to a lower side of the trailing shield layer. Moreover, the tapered face extends from a trailing edge of the pole tip at a constant inclination angle.