Write Head Side Shields With Antiferromagnetic Coupling
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Solution Overview
Problem
The use of side shields in write heads leads to cross-track gradients and side track erasure (STE) due to flux leakage, affecting areal density and write performance.
Innovation Solution
Incorporating antiferromagnetic-coupling layers between the trailing shield and side shields, and optionally using recessed or multi-layered side shields with different magnetic materials to minimize erasure fields and improve field uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If side shields are used in write heads, then cross-track gradients are improved, but side track erasure (STE) increases due to flux leakage
Solution Approach 1:
A non-magnetic gap is introduced as an intermediary element between the side shields and the trailing shield. This gap acts as a mediator that blocks the flux leakage path from the write pole to the side shields, thereby preventing side track erasure while preserving the beneficial cross-track gradient effects of the side shields.
Solution Approach 2:
The side shields are segmented into multiple layers with different magnetic properties. The first side shield layer has higher magnetic permeability and is positioned closer to the write pole, while the second side shield layer has lower magnetic permeability and is positioned farther away. This segmentation allows different layers to perform different functions in managing magnetic flux.
2Quantity of substance
If side shields are used in write heads, then areal density is improved, but flux leakage into media increases
Solution Approach 1:
The non-magnetic gap serves as a barrier that interrupts the flux leakage path into the magnetic media. By placing this gap between the side shields and the media interface, it prevents unwanted flux from reaching the media, thereby reducing energy loss while maintaining the areal density benefits provided by the side shields.
Solution Approach 2:
The side shield structure uses composite material configuration with two different magnetic layers. The first layer uses high permeability material to guide flux effectively, while the second layer uses low permeability material to reduce flux leakage into the media, creating a composite structure that optimizes both areal density and flux containment.
3Object-generated harmful factors
If antiferromagnetic-coupling layers are added between trailing shield and side shields, then erasure fields are reduced, but device complexity increases
Solution Approach 1:
The patent introduces antiferromagnetic-coupling layers that change the magnetic parameters of the shield structure. These layers modify the magnetic coupling between the trailing shield and side shields, altering the magnetic field distribution to reduce erasure fields. The coupling layers enable controlled magnetic interaction that suppresses unwanted erasure effects.
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
Significantly reduces erasure fields and cross-track gradients, enhancing write performance by preventing same-polarity charges from spreading and reducing magnetic flux leakage into the media.
Implementation Method 1
Incorporating antiferromagnetic-coupling layers between the trailing shield and side shields
Implementation Method 2
flux leakage through the flare angle into the side shields and into the media
Data Source
AI summary
A write head, the write head having an air bearing surface, the write head including a magnetic write pole, wherein at the air bearing surface, the write pole has a trailing surface, a leading surface that is opposite the trailing surface, and first and second surfaces; a trailing shield proximate the trailing surface of the magnetic write pole; first and second gaps proximate the first and second surfaces of the magnetic write pole; first and second side shields proximate the first and second gaps, each of the first and second side shields having a trailing shield surface; and first and second antiferromagnetic-coupling layers positioned between the trailing shield surfaces of the first and second side shields and the trailing shield.