Magnetic Write Pole With Layered Gradient For Side Writing Reduction
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Solution Overview
Problem
Magnetic write heads face challenges with side writing and side erasure due to magnetic flux leakage and fringing, which become more pronounced as areal density increases, limiting the effectiveness of existing shields in minimizing these issues.
Innovation Solution
The fabrication of a magnetic write pole with a layered structure, where multiple ferromagnetic layers with different magnetic moments are formed to increase the magnetic moment from the leading edge to the trailing edge, and a tapered sidewall is created to concentrate the magnetic field and reduce fringing effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If perpendicular recording is used to achieve larger areal densities, then storage capacity increases, but side writing and side erasure occur due to magnetic flux leakage and fringing
Solution Approach 1:
The write pole is divided into multiple ferromagnetic layers (first, second, and third layers) with different magnetic moments. The third ferromagnetic layer has a higher magnetic moment than the first layer, creating a gradient that concentrates magnetic flux at the trailing edge. This local variation in magnetic properties reduces flux leakage and fringing effects that cause side writing and erasure, while maintaining high areal density.
Solution Approach 2:
The write pole employs a composite structure consisting of multiple ferromagnetic layers with different magnetic moments. This composite material approach allows optimization of magnetic flux distribution, concentrating field strength where needed (trailing edge) while minimizing harmful leakage and fringing effects at the sides, thereby resolving the contradiction between high areal density and side writing/erasure prevention.
2Reliability
If magnetic flux is concentrated for writing, then writing effectiveness improves, but leakage and fringing increase causing side writing and erasure
Solution Approach 1:
By creating a magnetic moment gradient across the write pole layers (with the third layer having higher moment than the first), the invention concentrates magnetic flux locally at the trailing edge where it is needed for effective writing, while the varying magnetic moments across different layers and regions help contain the flux and reduce leakage and fringing that would otherwise cause side writing and erasure.
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 approach enhances the magnetic performance by reducing side writing and erasure errors, improving the ability to maintain high areal density while minimizing magnetic flux leakage and fringing, thereby enhancing the accuracy and efficiency of data writing on magnetic disks.
Implementation Method 1
forming a first ferromagnetic layer having a first magnetic moment, forming a second ferromagnetic layer adjacent to a sidewall portion of the first ferromagnetic layer, the second ferromagnetic layer having a second magnetic moment, and forming a third ferromagnetic layer on the first ferromagnetic layer and the second ferromagnetic layer, wherein the third ferromagnetic layer has a third magnetic moment greater than the first magnetic moment
Data Source
AI summary
Embodiments of the invention provide a magnetic recording head including a write pole having increasing magnetic moment from a leading edge of the write pole to a trailing edge of the write pole, and methods for manufacturing the same. The write pole may be formed with a plurality of different magnetic material layers having different magnetic moments. A first magnetic layer may be formed with a first magnetic material adjacent a leading edge of the write pole. A second magnetic layer having a greater moment may be formed on the first magnetic layer, thereby increasing the magnetic moment from the leading edge of the write pole to the trailing edge of the write pole.