Magnetic Write Head Non-Conformal Side Shield Gap
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Solution Overview
Problem
Existing magnetic write heads face challenges in achieving optimal write field gradient while minimizing adjacent track interference (ATI) and far track interference (FTI), as reducing the side gap thickness to enhance field gradient leads to decreased write field strength and potential magnetic flux concentration issues.
Innovation Solution
A magnetic write head design featuring a triangular cross-section write pole with a non-magnetic layer surrounding the leading edge and sides, where the side gap thickness is thinner than the leading gap, and the write pole bevel angle is greater than the shield bevel angle, forming an inverted trapezoidal shape to optimize performance and prevent asymmetrical structures that could cause interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the side gap thickness is reduced to enhance write field gradient, then write field gradient is improved, but write field strength decreases
Solution Approach 1:
The patent applies local quality by making the side gap thickness different from the leading gap thickness. Specifically, the side gap is configured with a first thickness while the leading gap has a second thickness, allowing different regions of the magnetic head to have optimized characteristics for their specific functions - the side gap optimized for field gradient and the leading gap for maintaining write field strength.
2Manufacturing precision
If the side gap thickness is reduced to enhance write field gradient, then write field gradient is improved, but adjacent track interference and far track interference increase due to magnetic flux concentration
Solution Approach 1:
The patent applies local quality by making the side gap thickness different from the leading gap thickness. Specifically, the side gap is configured with a first thickness while the leading gap has a second thickness, allowing different regions of the magnetic head to have optimized characteristics for their specific functions - the side gap optimized for field gradient and the leading gap for maintaining write field strength.
3Ease of manufacture
If asymmetrical structures are present in the shield, then manufacturing is simplified, but charge accumulation and magnetic field leakage occur causing interference
Solution Approach 1:
The patent applies asymmetry in a controlled manner by configuring the side gap with a different thickness than the leading gap, creating an intentional asymmetric structure. This controlled asymmetry prevents charge accumulation and magnetic field leakage that would occur with conventional symmetrical designs, while still maintaining ease of manufacture through standard fabrication processes.
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 enhances write field gradient, maintains magnetic field strength, and reduces ATI and FTI by controlling the relationship between leading and side gap thicknesses, preventing charge accumulation and magnetic field leakage, thus improving data writing efficiency and accuracy.
Implementation Method 1
An electrically conductive write coil induces a magnetic flux through the write coil. This results in a magnetic write field being emitted toward the adjacent magnetic medium
Implementation Method 2
A non-magnetic layer surrounding the leading edge and the sides of the write pole... the non-magnetic layer can be formed with a non-uniform thickness so that the side gap thickness at the trailing edge of the write pole is different than the thickness of the gap at side gap and leading gap
Implementation Method 3
A magnetoresistive sensor such as a GMR or TMR sensor can be employed for sensing magnetic fields from the rotating magnetic disk... Changes in scattering alter the resistance of the spin valve sensor in proportion to cos θ
Data Source
AI summary
A magnetic write head having a shield structure that provides both a leading shield and side shielding function. The magnetic shield is separated from the sides and leading edge of the write pole by a non-magnetic gap layer that has a non-uniform thickness. The non-magnetic gap layer is thicker near the leading edge and thinner at the trailing edge. This allows for increased side field gradient near the trailing edge of the write pole and decreased write field loss at the leading edge of the write pole.