Magnetic Writer Main Pole Curved Sidewalls
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current magnetic recording writers, such as PMR and MAMR, face challenges in achieving balanced main pole volume distribution, leading to limitations in areal density capacity due to unbalanced volume distribution and flux leakage, which affects writeability and bit density.
Innovation Solution
The design incorporates a main pole with a front and back portion, a gap layer, and an all-wrap-around shield structure, featuring curved and flared sidewalls, tapered portions, and strategically positioned shields to enhance volume balance and field gradients, resulting in improved areal density capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the main pole size is shrunk to increase areal density, then higher bits per inch and tracks per inch can be achieved, but writeability degrades
Solution Approach 1:
The patent changes the geometric parameters of the main pole, specifically transitioning from a conventional rectangular cross-section to a rounded rectangular cross-section with curved sidewalls. This parameter change optimizes the magnetic field distribution, maintaining writeability while enabling smaller pole dimensions for higher areal density.
Solution Approach 2:
The patent applies curvature to the main pole sidewalls, creating a rounded rectangular cross-section instead of sharp edges. This curvature modifies the magnetic flux distribution, reducing flux leakage and improving field gradients, which sustains writeability at reduced pole sizes.
2Productivity
If the main pole volume is increased in cross-track dimension to improve track field gradient, then tracks per inch improves, but the volume distribution becomes unbalanced
Solution Approach 1:
The patent applies different geometric characteristics to different parts of the main pole: curved sidewalls in the cross-track direction to improve track field gradient and TPI, while maintaining appropriate dimensions in the down-track direction. This local optimization achieves balanced volume distribution with improved performance in both dimensions.
3Productivity
If thinner side gaps are used to increase bits per inch, then cross-track field gradient improves, but flux leakage increases
Solution Approach 1:
The curved sidewalls of the main pole modify the magnetic flux distribution in the side gaps. The curvature creates a more gradual field transition, reducing flux leakage while maintaining the thin gap dimensions necessary for high bits per inch and improved cross-track field gradient.
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 achieves a better balanced volume distribution, enhancing areal density capacity while maintaining writeability, with improved cross-track and down-track field gradients, leading to increased bits per inch and tracks per inch without compromising writeability.
Implementation Method 1
There is always flux leakage between the side shields and main pole due to thin side gaps in current writer designs
Data Source
AI summary
A magnetic recording writer is disclosed. In some embodiments, the writer includes a main pole having a front portion and a back portion, a gap layer surround the main pole at the ABS, and a shield structure. The front portion includes a pole tip at an ABS plane, a pole tip thickness in a down-track direction, and curved sidewalls on each side of a center plane that is orthogonal to the ABS and bisects the main pole. The back portion includes first flared sidewalls extending from the curved sidewalls at an angle between 0 and 25 degrees relative to planes parallel to the center plane. The shield structure includes sidewalls having a sidewall portion facing the main pole and formed substantially conformal to the curved sidewalls up to a height of about 30-200 nm where the sidewall portions no longer follow the shape of the main pole.