Magnetic Head With Integrated Side Shields For Perpendicular Recording
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording face issues with magnetic field leakage, which can destabilize the magnetization of the recording layer and degrade recorded data, leading to errors and reduced recording density.
Innovation Solution
The magnetic head design includes a main pole, a return pole, side shields, and a second magnetic core with a coil to form a closed magnetic path, suppressing magnetic flux leakage and preventing data degradation by controlling the magnetic field to ensure accurate recording and increased track density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a return pole is provided to close the magnetic path, then magnetic flux is contained, but concentrated magnetic fields appear just below the return pole that may destabilize magnetization and erase recorded data
Solution Approach 1:
The return pole is segmented into a first return pole and a second return pole positioned at different locations. The first return pole closes the magnetic path for the main pole, while the second return pole is positioned to avoid concentrated magnetic fields. This segmentation allows the magnetic path to be closed without creating harmful concentrated fields that would destabilize magnetization in the recording layer.
Solution Approach 2:
A shield structure is introduced as an intermediary element between the main pole and the recording layer. The shield prevents magnetic flux from directly reaching the recording layer through the return pole, thereby blocking the harmful concentrated magnetic fields while still allowing the magnetic path to be closed for efficient recording.
2Object-affected harmful factors
If side shields are arranged individually on opposite sides of the main pole, then leakage magnetic fields are reduced, but the structure becomes more complex
Solution Approach 1:
The side shields are merged with the return pole structure to form an integrated configuration. Instead of being separate individual components, the side shields are combined with the return pole to create a unified structure that reduces leakage magnetic fields while minimizing the overall number of discrete parts and simplifying assembly.
3Productivity
If track density is increased to improve recording capacity, then more data can be stored, but magnetic field leakage to adjacent tracks increases causing data errors
Solution Approach 1:
The shield structure serves as an intermediary barrier between adjacent tracks. It blocks magnetic flux from leaking from one track to another, enabling higher track densities without the harmful cross-track magnetic field interference that would otherwise cause data errors and reduce recording capacity.
Solution Approach 2:
The magnetic head is segmented into functionally independent regions with dedicated return poles for each track. This segmentation isolates the magnetic fields to specific tracks, preventing leakage to adjacent tracks and allowing increased track density while maintaining data integrity.
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 reduces magnetic field leakage, maintains data integrity, and increases recording density by preventing data erasure in adjacent tracks while maintaining recording capacity on the write track.
Implementation Method 1
a main pole configured to produce a perpendicular magnetic field
Implementation Method 2
The coil serves to pass magnetic flux through the main pole
Implementation Method 3
a return pole opposed to a trailing side of the main pole with a write gap therebetween and configured to close a magnetic path that leads to a magnetic disk
Implementation Method 4
side shields arranged individually on opposite sides of the main pole transversely relative to the track so as to suppress leakage magnetic fields from the main pole
Implementation Method 5
a second magnetic core configured to form a physically closed magnetic path, a part of which comprises the return pole
Data Source
AI summary
According to one embodiment, a magnetic head for perpendicular recording includes a first magnetic core includes a main pole configured to produce a recording magnetic field, and a return pole configured to reflux magnetic flux from the main pole to form a magnetic circuit in conjunction with the main pole, a first coil configured to excite magnetic flux in the magnetic circuit, side shields arranged individually on opposite sides of the main pole transversely relative to a track so as to be magnetically separated from the main pole and formed integrally with the return pole, a second magnetic core configured to form a physically closed magnetic path, a part of which comprises the return pole, and a second coil wound around the second magnetic core and configured to excite magnetic flux in the closed magnetic path.