Perpendicular Magnetic Head Yoke Segmentation for Field Strength
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording face challenges in producing a sufficient write magnetic field while reducing the length of the magnetic path between the write shield and the main pole, which affects recording density and leads to unwanted erasure of adjacent tracks.
Innovation Solution
The magnetic head design includes a write shield with a yoke layer on both the front and rear sides of the main pole, utilizing multiple magnetic path portions and a zigzag winding of the coil to generate opposing magnetic fields, allowing for a reduced magnetic path length while maintaining a sufficient write magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the magnetic path length between the write shield and the main pole is reduced, then recording density is improved, but the write magnetic field magnitude decreases
Solution Approach 1:
The yoke layer is divided into multiple segments (first yoke layer, second yoke layer, third yoke layer) that are positioned at different locations. Each segment contributes to the magnetic flux return path, allowing the magnetic path length to be reduced while maintaining sufficient write magnetic field through the coordinated action of multiple segmented components rather than a single continuous structure
Solution Approach 2:
The patent introduces a vertical dimension to the magnetic path configuration by stacking multiple yoke layers at different heights above the substrate. This multi-layer arrangement allows the magnetic flux to return through a three-dimensional path, effectively reducing the horizontal magnetic path length while maintaining the overall magnetic circuit efficiency and write field magnitude
2Object-generated harmful factors
If the magnetic path length is reduced, then unwanted erasure of adjacent tracks is prevented, but the write magnetic field strength is compromised
Solution Approach 1:
The yoke layer is divided into multiple segments (first yoke layer, second yoke layer, third yoke layer) that are positioned at different locations. Each segment contributes to the magnetic flux return path, allowing the magnetic path length to be reduced while maintaining sufficient write magnetic field through the coordinated action of multiple segmented components rather than a single continuous structure
Solution Approach 2:
The patent introduces a vertical dimension to the magnetic path configuration by stacking multiple yoke layers at different heights above the substrate. This multi-layer arrangement allows the magnetic flux to return through a three-dimensional path, effectively reducing the horizontal magnetic path length while maintaining the overall magnetic circuit efficiency and write field magnitude
3Force
If multiple yoke layers are added to reduce magnetic path length, then write magnetic field is maintained, but device complexity increases
Solution Approach 1:
Multiple yoke layers are merged into a single integrated yoke structure that performs the functions of all layers simultaneously. This consolidation reduces the number of separate components and simplifies the overall device structure while maintaining the benefits of multiple magnetic paths for reduced magnetic path length and sustained write field magnitude
Solution Approach 2:
The integrated yoke structure serves multiple functions: it provides magnetic flux return paths, defines track boundaries, and maintains write field magnitude. By combining these functions into a single multi-functional component, the device complexity is reduced while achieving the desired performance benefits
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 enables the production of a write magnetic field of sufficient magnitude while minimizing the length of the magnetic path, thereby enhancing recording density and preventing unwanted erasure of adjacent tracks.
Implementation Method 1
a coil producing a magnetic field corresponding to data to be written on the recording medium
Implementation Method 2
The main pole allows a magnetic flux corresponding to the magnetic field produced by the coil to pass, and produces a write magnetic field from its end face
Implementation Method 3
The write shield and the return path section have the function of capturing a magnetic flux that is produced from the end face of the main pole and spreads in directions other than a direction perpendicular to the plane of the recording medium, so as to prevent the magnetic flux from reaching the recording medium
Data Source
AI summary
A magnetic head includes a coil, a main pole, a write shield, first and second yoke layers, and first and second coupling parts. The first yoke layer is located on the trailing side relative to the main pole whereas the second yoke layer is located on the leading side relative to the main pole. The first coupling part couples the main pole and the first yoke layer to each other. The second coupling part couples the first yoke layer and the second yoke layer to each other. The first coupling part includes a plurality of first magnetic path portions, and the second coupling part includes a plurality of second magnetic path portions. The coil includes one winding portion extending to pass around the first and second magnetic path portions alternately in a zigzag manner.