Recessed Trailing Shield and Return Pole for Magnetic Write Head
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Solution Overview
Problem
Magnetic data recording faces challenges with far track interference, where stray magnetic fields from the trailing shield and return pole inadvertently magnetize adjacent tracks, leading to data corruption and reduced areal density due to potential contact with the media.
Innovation Solution
The magnetic write head features a trailing shield and return pole that are recessed and tapered away from the media-facing surface, creating a non-magnetic gap to prevent stray fields while maintaining an effective return path for the magnetic write field, with a taper angle of 7-9 degrees optimally balancing interference prevention and writing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the trailing shield and return pole are positioned close to the media facing surface, then the magnetic return path is efficient for writing, but far track interference occurs due to stray magnetic fields inadvertently magnetizing adjacent tracks
Solution Approach 1:
The trailing shield and return pole are recessed from the media facing surface into the slider body, transitioning from a planar configuration to a three-dimensional recessed structure. This dimensional change creates physical separation that reduces stray magnetic field exposure to the media while preserving the magnetic return path through the magnetically soft material.
Solution Approach 2:
A non-magnetic gap layer is introduced between the write pole and the trailing shield, and a magnetic gap layer is positioned between the trailing shield and return pole. These intermediary layers mediate the magnetic field paths, preventing direct magnetic coupling that would cause far track interference while maintaining the necessary return path functionality.
2Object-generated harmful factors
If the trailing shield and return pole are recessed from the media facing surface, then far track interference is prevented, but the magnetic return path efficiency may be compromised
Solution Approach 1:
The write head employs composite material construction with magnetically soft materials for the trailing shield and return pole, combined with non-magnetic gap layers and magnetic gap layers. This composite structure enables the recessed configuration to block stray fields while the magnetically soft materials provide efficient flux return paths through their high permeability properties.
Solution Approach 2:
The magnetic permeability and thickness parameters of the trailing shield and return pole are optimized to maintain sufficient return path efficiency despite the recessed configuration. By adjusting these parameters, the design ensures that the magnetic flux can still effectively return through the recessed structures without compromising writing performance.
3Quantity of substance
If the trailing shield and return pole contact the media, then areal density can be increased, but data corruption occurs due to inadvertent magnetization of adjacent tracks
Solution Approach 1:
The trailing shield and return pole are recessed from the media facing surface into the slider body, creating a three-dimensional configuration that prevents contact with the media. This dimensional change allows the head to operate at lower fly-heights for increased areal density while the recessed structure physically isolates the magnetic components from the media to prevent data corruption.
4Quantity of substance
If the trailing shield and return pole are recessed, then lower fly-heights are enabled for higher areal density, but manufacturing complexity increases
Solution Approach 1:
The trailing shield and return pole are segmented as separate recessed components within the slider body, allowing independent positioning and optimization of each element. This segmentation enables the complex three-dimensional recessed structure to be manufactured using standard semiconductor fabrication techniques, reducing overall manufacturing complexity despite the advanced geometry.
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 design effectively minimizes far track interference, allows for lower fly-heights, and increases areal density by preventing inadvertent contact and ensuring sufficient magnetic field return, thereby enhancing data recording accuracy and storage capacity.
Implementation Method 1
a trailing magnetic shield that is separated from the trailing edge of the write pole by a non-magnetic trailing gap layer
Implementation Method 2
A magnetoresistive sensor such as a Giant Magnetoresistive (GMR) sensor
Implementation Method 3
Tunnel unction Magnetoresistive (TMR) sensor
Implementation Method 4
When current flows through the coil, a resulting magnetic field causes a magnetic flux to flow through the coil, which results in a magnetic write field emitting from the tip of the write pole
Data Source
AI summary
A magnetic write head having trailing magnetic shield and a trailing magnetic return pole that are recessed from the media facing surface. The magnetic write head includes a write pole, a trailing shield that is separated from the write pole by a non-magnetic trailing gap layer and a trailing magnetic return pole that is connected with the trailing magnetic shield. The trailing magnetic return pole and at least a portion of the trailing magnetic shield have surfaces that face the media facing surface. The surface of the trailing magnetic return pole and at least a portion of the surface of the trailing magnetic shield taper away from the media facing surface. This recess prevents far track interference by preventing stray magnetic fields from the trailing magnetic shield and trailing magnetic return pole from inadvertently affecting the magnetic media.