Virtual Side Shield Design for Magnetic Recording Areal Density
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Solution Overview
Problem
Magnetic recording devices face challenges with erasure of adjacent tracks and magnetic shunting due to side shields, which affect areal density and bits per inch performance.
Innovation Solution
A magnetic recording device design incorporating a virtual side shield with a heavy metal first layer and a magnetic second layer, where the second layer has a greater thickness than the first layer, surrounding specific surfaces of the main pole to reduce erasure and shunting, and the layers have a total thickness between about 2 nm to about 20 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If side shields are added to reduce erasure in adjacent tracks, then tracks per inch performance is improved, but magnetic shunting occurs in side gaps reducing bits per inch
Solution Approach 1:
The patent changes the material composition and thickness parameters of the side shield, using a composite structure with a first layer (5-15 nm) and a second layer (10-20 nm) with specific magnetic properties (Ms=500-2000 emu/cc) to optimize both erasure prevention and magnetic flux containment, resolving the contradiction between reducing adjacent track erasure and preventing magnetic shunting
Solution Approach 2:
The side shield is constructed as a composite structure with two distinct layers having different magnetic properties - a first layer with lower magnetization and a second layer with higher magnetization, creating a gradient that prevents both erasure in adjacent tracks and shunting in side gaps, thereby improving both tracks per inch and bits per inch performance
2Object-affected harmful factors
If side shields are added to improve tracks per inch, then adjacent track erasure is reduced, but device complexity increases
Solution Approach 1:
The patent optimizes the thickness parameters of the side shield layers (first layer: 5-15 nm, second layer: 10-20 nm) and magnetic properties (Ms=500-2000 emu/cc) to achieve effective erasure prevention with minimal structural complexity, using parameter optimization rather than complex geometric designs
Solution Approach 2:
The side shield structure applies different material properties and thicknesses at different locations and orientations relative to the main pole, with the first layer providing baseline shielding and the second layer enhancing protection in critical regions, achieving effective erasure prevention with optimized local properties rather than uniform complex structure
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 virtual side shield effectively prevents erasure of adjacent tracks, increases bits per inch, and enhances overwrite capability without compromising tracks per inch or adjacent track interference, thereby improving areal density and performance.
Implementation Method 1
A side shield surrounds the main pole and comprises a heavy metal first layer and a magnetic second layer
Implementation Method 2
a magnetic recording device comprises a main pole having a first surface adjacent to a trailing gap, a second surface adjacent to the first surface, a third surface opposite the second surface, and a fourth surface adjacent to a leading gap
Data Source
AI summary
Embodiments of the present disclosure generally relate to a magnetic media drive employing a magnetic recording device. The magnetic recording device comprises a trailing gap disposed adjacent to a first surface of a main pole, a first side gap disposed adjacent to a second surface of the main pole, a second side gap disposed adjacent to a third surface of the main pole, and a leading gap disposed adjacent to a fourth surface of the main pole. A side shield surrounds the main pole and comprises a heavy metal first layer and a magnetic second layer. The first layer surrounds the first, second, and third surfaces of the main pole, or the second, third, and fourth surfaces of the main pole. The second layer surrounds the second and third surfaces of the main pole, and may further surround the fourth surface of the main pole.