Thin Shield Structures for Sensor Array Alignment
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Solution Overview
Problem
Designing sensor assemblies with multiple sensors positioned closely together is challenging, particularly for vertically arranged sensor arrays in two-dimensional magnetic recording technology, due to misalignment issues that increase with vertical separation between sensors.
Innovation Solution
The use of thin shield structures with unique shape anisotropy and laminated soft ferromagnetic layers reduces shield-to-shield spacing and stabilizes magnetization, while a hybrid soft and hard bias scheme offsets the loss in pinning strength associated with reduced thickness, allowing for ultra-thin middle shield stacks and improved noise absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vertical separation between sensors is reduced to reduce skew sensitivity, then measurement precision is improved, but manufacturing precision becomes more difficult to achieve
Solution Approach 1:
Thin shield structures serve as intermediary elements positioned between adjacent sensors in the vertical array. These shields act as mediators that enable closer vertical spacing by providing magnetic isolation and reducing skew sensitivity, while the shield's physical structure helps maintain alignment between sensors. The shield's presence facilitates reduced vertical separation without compromising manufacturing precision.
Solution Approach 2:
The patent changes the thickness parameter of the shield structures to ultra-thin dimensions. This parameter change enables reduced vertical separation between sensors while maintaining adequate magnetic shielding performance. By optimizing the shield thickness to be as thin as possible while maintaining functionality, the patent achieves both improved measurement precision and feasible manufacturing precision.
2Device complexity
If shield thickness is reduced to reduce vertical separation, then device complexity is reduced, but stability of magnetization becomes compromised
Solution Approach 1:
The shield structures are constructed using composite material stacks consisting of multiple ferromagnetic layers with different properties. These composite shields provide enhanced magnetization stability despite reduced overall thickness. The combination of different ferromagnetic materials creates a multi-layer structure that maintains magnetic stability while achieving the desired thin profile for reduced vertical separation.
Solution Approach 2:
The shield is divided into multiple segmented ferromagnetic layers stacked together. This segmentation allows each layer to contribute specific magnetic properties, with the collective effect providing stable magnetization. The segmented structure enables the shield to maintain adequate thickness for stability while appearing thinner overall, facilitating reduced vertical separation between sensors.
3Productivity
If vertical separation between sensors is reduced, then productivity is improved, but reliability decreases due to increased misalignment
Solution Approach 1:
The thin shield structures serve as intermediary elements that enable higher sensor array density by allowing reduced vertical separation. Simultaneously, the shields act as alignment references that maintain reliability. The shield's physical presence and magnetic properties work together to ensure that sensors positioned closer together still maintain adequate alignment accuracy, thus achieving both improved productivity and maintained reliability.
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 approach effectively reduces vertical separation between sensors, enhances stability and shielding performance, and maintains a balance between stability and thickness, addressing misalignment and noise issues in two-dimensional magnetic recording.
Implementation Method 1
thin shield structures with unique shape anisotropy and laminated soft ferromagnetic layers reduces shield-to-shield spacing and stabilizes magnetization
Implementation Method 2
laminated soft ferromagnetic layers reduces shield-to-shield spacing and stabilizes magnetization
Implementation Method 3
hybrid soft and hard bias scheme offsets the loss in pinning strength associated with reduced thickness
Data Source
AI summary
Apparatuses and methods for providing thin shields in a multiple sensor array are provided. One such apparatus is a magnetic read transducer including a first read sensor, a second read sensor, and a shield assembly positioned between the first read sensor and the second read sensor at an air bearing surface (ABS) of the magnetic read transducer, the shield assembly including a first shield layer assembly having a first footprint with a first area, and a second shield layer assembly having a second footprint with a second area, where the second area is greater than the first area.