Perpendicular Magnetic Recording Head Pole Layer Trapezoidal Flared Part
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Solution Overview
Problem
Perpendicular magnetic recording heads face challenges in maintaining high recording density due to increased side fringe width caused by leakage magnetic fields from the flared part of the main magnetic pole layer, which broadens the magnetic flux and leads to data deletion on adjacent tracks.
Innovation Solution
The design incorporates a main magnetic pole layer with a trapezoidal shape for both the pole straight part and the flared part, narrowed at the nonmagnetic insulating layer-side, to reduce leakage magnetic fields by beveling, thereby preventing side fringing and enhancing recording density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the recording magnetic field intensity is increased to achieve higher recording density, then the recording density is improved, but the side fringe width increases causing information deletion on adjacent tracks
Solution Approach 1:
The main magnetic pole layer is divided into three distinct segments: a pole tip part with a first cross-sectional shape, a pole straight part with a second cross-sectional shape, and a flared part with a third cross-sectional shape. Each segment has optimized geometry to control magnetic flux distribution, with the pole tip providing field concentration and the pole straight part maintaining a narrower width to reduce side fringe effects.
Solution Approach 2:
Different portions of the main magnetic pole layer are given different local geometries and magnetic properties. The pole tip part has a specific cross-sectional shape optimized for field generation, the pole straight part has a narrower cross-section to constrain flux, and the flared part has a specific geometry to control leakage. This local differentiation allows the structure to simultaneously achieve high field intensity and minimal side fringe.
2Object-generated harmful factors
If the pole straight part cross-sectional width is reduced to minimize side fringe width, then the side fringe width is decreased, but the recording magnetic field intensity is reduced
Solution Approach 1:
The solution moves from considering only the cross-sectional width (one dimension) to optimizing the three-dimensional geometry of the entire pole structure. By controlling the length, width, and shape variations along the height direction, the patent achieves both high field intensity and minimal side fringe through spatial configuration rather than simple width reduction.
Solution Approach 2:
The cross-sectional dimensions of the main magnetic pole layer are made dynamic rather than uniform. The width varies along the height direction, with the pole tip having one width, the pole straight part having a narrower width, and the flared part having an intermediate width. This dynamic geometry allows optimization of both field intensity and side fringe control at different locations.
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 suppresses side fringe width and allows for higher recording density by concentrating the magnetic field and reducing leakage, even under high recording magnetic field intensities.
Implementation Method 1
Once electricity is supplied to the coil layer, a recording magnetic field is induced between the main magnetic pole layer and the return path layer
Implementation Method 2
a recording magnetic field is induced between the main magnetic pole layer and the return path layer and enters a hard film of the recording medium in a perpendicular fashion
Data Source
AI summary
A perpendicular magnetic recording head includes a nonmagnetic insulating layer and a main magnetic pole layer disposed on the nonmagnetic insulating layer. The main magnetic pole layer includes a pole straight part exposed in an opposing surface opposite a recording medium and a flared part that extends from the pole straight part in a height direction. The flared part broadens in a track width direction as the flared part extends in the height direction. The pole straight part of the main magnetic pole layer as viewed from the opposing surface has a trapezoidal shape over its entire length, the trapezoidal shape being narrowed at the nonmagnetic insulating layer-side. The flared part as viewed from the opposing surface has a trapezoidal shape at least at a junction with the pole straight part, the trapezoidal shape being narrowed at the nonmagnetic insulating layer-side.