Perpendicular Magnetic Recording Head Asymmetric Shielding
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Solution Overview
Problem
Conventional perpendicular magnetic recording heads face challenges in maintaining high recording density and preventing data loss due to magnetic field leakage and intensity reduction, particularly when using soft magnetic films to shield the main pole.
Innovation Solution
The design incorporates first and second magnetic films with varying depths and tapered portions, where the first films are thinner and positioned on both sides of the main pole, and the second film is thicker on the trailing side, with nonmagnetic films in between, to control the magnetic field and prevent data loss on adjacent tracks without reducing the magnetic field intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If soft magnetic films are used to shield the main pole, then magnetic field leakage toward adjacent tracks is prevented, but magnetic field intensity is reduced
Solution Approach 1:
The patent applies local quality by creating asymmetric magnetic film structures with different depths at different locations. The first magnetic films are positioned at a first depth from the air bearing surface, while the second magnetic film is positioned at a second depth, allowing different regions to have optimized magnetic shielding properties. This enables prevention of magnetic field leakage toward adjacent tracks while maintaining sufficient magnetic field intensity for recording.
Solution Approach 2:
The patent introduces depth as an additional dimensional parameter for magnetic film positioning. Instead of only varying lateral positions, the invention utilizes the depth dimension from the air bearing surface to create asymmetric shielding structures. This dimensional approach allows independent optimization of shielding effectiveness and magnetic field intensity by controlling film depths.
2Ease of manufacture
If symmetric magnetic films are used on both sides of the main pole, then manufacturing is simplified, but magnetic field gradient is insufficient for high-density recording
Solution Approach 1:
The patent explicitly employs asymmetry by positioning the first magnetic films at a first depth and the second magnetic film at a second depth, creating an asymmetric magnetic shielding structure. This asymmetric configuration generates an optimized magnetic field gradient that enables high-density recording, while the systematic approach to creating this asymmetry maintains reasonable manufacturing feasibility.
3Object-affected harmful factors
If magnetic films are positioned deeper from the air bearing surface, then shielding effectiveness increases, but magnetic field intensity at the recording medium decreases
Solution Approach 1:
The patent utilizes parameter changes by optimizing the depth parameters of magnetic films from the air bearing surface. The first magnetic films are positioned at a specifically optimized first depth, and the second magnetic film at a second depth, balancing the competing requirements of shielding effectiveness and magnetic field intensity. This parameter optimization enables both leakage prevention and sufficient recording field strength.
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 the gradient and intensity of the magnetic field, allowing for high-density recording without data loss on adjacent tracks, by optimizing the depth and shape of the magnetic films relative to the air bearing surface.
Implementation Method 1
a recording magnetic field corresponding to the current polarity is generated from the main pole
Implementation Method 2
The soft magnetic underlayer has a function of returning a magnetic flux acting on the recording layer to the auxiliary pole
Implementation Method 3
first magnetic films arranged on both sides of the main pole in a track width direction via nonmagnetic films
Data Source
AI summary
A perpendicular magnetic recording head according to one embodiment includes a main pole; first magnetic films arranged on both sides of the main pole in a track width direction via nonmagnetic films; and a second magnetic film arranged on a trailing side of the main pole via a nonmagnetic film; wherein the depths of the first magnetic films from an air bearing surface are smaller than the depth of the second magnetic film from the air bearing surface at least at a periphery of the main pole. A perpendicular magnetic recording head according to another embodiment includes a main pole; first magnetic films arranged on both sides of the main pole in a track width direction via nonmagnetic films; and a second magnetic film arranged on a trailing side of the main pole via a nonmagnetic film; wherein the main pole and the first magnetic films have respective tapered portions whose thicknesses become larger toward the side opposite to an air bearing surface, and the tapered portions are in contact with the second magnetic film. Additional embodiments are also presented.