Magnetic Write Pole Curvature and Chisel Angle Profiles
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Solution Overview
Problem
Conventional magnetic recording transducers experience performance degradation at higher recording densities due to reduced physical geometry of the main pole, leading to a loss in write field and increased reverse overwrite issues.
Innovation Solution
The magnetic recording transducer design incorporates a main pole with a varying radius of curvature and chisel angle, where the chisel angle increases to a maximum and the radius of curvature has a minimum distance from the air-bearing surface, enhancing the effective magnetic volume and write field magnitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the main pole is scaled down in size to increase recording density, then the recording density increases, but the write field strength is reduced
Solution Approach 1:
The patent applies local quality by creating a non-uniform radius of curvature profile along the pole tip, where the curvature varies at different locations to locally enhance the magnetic field. Specifically, the pole tip has a minimum radius of curvature at a specific distance from the air-bearing surface, creating a concentrated field region that compensates for the overall size reduction of the main pole.
Solution Approach 2:
The patent changes the geometric parameters of the main pole by introducing a varying radius of curvature profile and optimized chisel angle. Instead of uniform dimensions, the pole tip geometry is modified with specific curvature radii (e.g., minimum radius of curvature between 50-150 nm) and angle variations, which fundamentally alters the magnetic field distribution to maintain write field strength despite reduced pole size.
2Quantity of substance
If the main pole size is reduced to increase recording density, then the recording density increases, but reverse overwrite issues increase
Solution Approach 1:
The patent uses local quality by creating a concentrated magnetic field region at the pole tip through controlled curvature variations. This localized field enhancement ensures reliable writing at the track center while preventing excessive field spread that causes reverse overwrite, thereby improving reliability at high recording densities.
Solution Approach 2:
The patent applies curvature principles by designing the pole tip with a specific radius of curvature profile. The rounded pole tip geometry with minimum radius of curvature at a controlled distance from the air-bearing surface creates a more uniform and controlled magnetic field distribution, reducing the harmful effects of reverse overwrite while maintaining high recording density.
3Quantity of substance
If the main pole size is reduced to increase recording density, then the recording density increases, but adjacent track interference increases
Solution Approach 1:
The patent applies local quality by concentrating the magnetic field at the pole tip through controlled curvature variations. This localized field confinement prevents magnetic field leakage into adjacent tracks, reducing adjacent track interference while maintaining high recording density.
Solution Approach 2:
The patent uses a rounded pole tip geometry with specific radius of curvature to create a more confined and uniform magnetic field. This curved geometry reduces field fringing and lateral spread, thereby minimizing interference with adjacent tracks while enabling higher recording densities.
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 improves writability and error margin, reducing adjacent track interference and wide area track erasure, resulting in enhanced overall performance at higher recording densities.
Implementation Method 1
The main pole 20 resides on an underlayer 12 and includes sidewalls 22 and 24. The magnetic recording transducer may be a perpendicular magnetic recording (PMR) head.
Data Source
AI summary
A magnetic transducer has air-bearing surface (ABS) and includes a main pole and at least one coil. The coil(s) energize the main pole. The main pole includes a yoke and a pole tip having an ABS-facing surface. The pole tip includes a sidewall having a radius of curvature and a chisel angle. The chisel angle is measured between a yoke direction perpendicular to the ABS and a tangent the sidewall. The chisel angle for the pole tip continuously increases in the yoke direction to a maximum a first distance from the ABS-facing surface in the yoke direction. The radius of curvature for the pole tip has a minimum radius of curvature a second distance from the ABS-facing surface in the yoke direction. The first distance is greater than the second distance.