Perpendicular Magnetic Head Write Shield Segmentation
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording face challenges in preventing unwanted erasure due to skew issues, where signals on adjacent tracks are erased or attenuated, and existing write shields suffer from flux saturation and inefficiency.
Innovation Solution
A magnetic head design incorporating a write shield made of magnetic material, a gap part made of nonmagnetic material, and a return path section made of magnetic material, with the write shield having end faces on opposite sides of the main pole to capture and redirect magnetic flux, preventing unwanted erasure by ensuring efficient flux utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a write shield is provided in the vicinity of the main pole to prevent unwanted erasure, then recording density is improved, but the write shield suffers from flux saturation and becomes inefficient
Solution Approach 1:
The write shield is divided into multiple segments: first and second write shields positioned on opposite sides of the main pole, with optional third and fourth write shields on the leading and trailing sides. This segmentation allows each shield segment to capture flux in specific directions without saturating, as the flux is distributed across multiple paths rather than concentrated in a single shield structure.
Solution Approach 2:
A nonmagnetic gap part is introduced as an intermediary element positioned between the main pole and the write shields. This gap part serves as a mediator that controls the magnetic flux distribution, preventing direct flux saturation in the write shields while maintaining their shielding function. The gap part allows precise control over flux capture and redirection.
2Object-affected harmful factors
If the write shield captures magnetic flux to prevent unwanted erasure, then adjacent track erasure is reduced, but flux leakage occurs and reduces overall efficiency
Solution Approach 1:
Different regions of the magnetic head structure are assigned different material properties: the write shields and main pole use magnetic materials to capture and guide flux, while the gap part uses nonmagnetic material to control flux distribution. This local differentiation of material properties ensures that flux is captured where needed (at the write shields) while preventing unwanted leakage paths, thereby reducing adjacent track erasure without significant flux loss.
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
The design effectively prevents unwanted erasure by capturing and redirecting magnetic flux, enhancing recording density and reducing flux leakage, thus improving the overall performance of the magnetic head.
Implementation Method 1
a coil that produces a magnetic field corresponding to data to be written on a 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 for writing the data on the recording medium
Implementation Method 3
The write shield has the function of capturing a magnetic flux that is produced from the end face of the main pole and spreads in directions other than the direction perpendicular to the plane of the recording medium
Implementation Method 4
The gap part is interposed between the main pole and the write shield
Implementation Method 5
The write shield and the return path section allow a magnetic flux that has been produced from the end face of the main pole and has magnetized the recording medium to flow back to the main pole
Data Source
AI summary
A magnetic head includes a main pole, a write shield, and a return path section. The write shield includes first and second shield portions located on opposite sides of the main pole in the track width direction. The return path section includes first and second yoke portions located on opposite sides of the main pole in the track width direction. The first yoke portion is connected to the first shield portion. The second yoke portion is connected to the second shield portion. A coil surrounds at least part of the entire outer periphery of the main pole when viewed from a medium facing surface.