TMR Read Head with Recessed AFM Layer for Narrow Shield Spacing
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Solution Overview
Problem
Current tunnel magnetoresistance (TMR) read heads struggle to narrow shield-to-shield spacing without losing magnetic directionality, as attempts to remove the antiferromagnet (AFM) layer result in magnetically bi-directional read heads.
Innovation Solution
The use of a tabbed AFM layer and an extended pinned layer with a recessed design, where the AFM layer and stitching layer are positioned beneath the air-bearing surface, allowing for thinner AFM layers without increasing shield-to-shield distance, and employing specific materials like IrMn and CoFe to maintain magnetic pinning and directionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the AFM layer is removed to narrow shield-to-shield spacing, then shield-to-shield spacing is reduced, but magnetic bi-directionality issues occur
Solution Approach 1:
The AFM layer is positioned in a recessed region below the air-bearing surface rather than extending to the top surface, utilizing the vertical dimension to reduce shield-to-shield spacing while maintaining magnetic pinning function through the stitching layer coupling to the pinned layer
Solution Approach 2:
The AFM layer is segmented into a recessed portion below the air-bearing surface and a top portion that may be removed, allowing the shield-to-shield spacing to be narrowed by removing the top portion while the recessed portion maintains the magnetic pinning function
2Length of stationary object
If the AFM layer is made thinner to reduce shield-to-shield spacing, then shield-to-shield spacing is reduced, but magnetic pinning strength may be compromised
Solution Approach 1:
The stitching layer acts as an intermediary between the AFM layer and the pinned layer, providing magnetic coupling and pinning strength even when the AFM layer is made thinner or recessed, thereby maintaining magnetic pinning strength while enabling reduced shield-to-shield spacing
Solution Approach 2:
The magnetic pinning mechanism is transitioned from relying solely on the AFM layer thickness to utilizing the coupling between the stitching layer and pinned layer, allowing thin AFM layers to provide sufficient pinning strength through this parameter change in the magnetic coupling mechanism
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 enables narrower track widths and shield-to-shield spacing while maintaining magnetic directionality, enhancing magnetic recording density without the bi-directional issues of AFM-free TMR read heads.
Implementation Method 1
Current tunnel magnetoresistance (TMR) read heads comprise a pinned layer coupled to an antiferromagnet (AFM) layer
Implementation Method 2
tunnel magnetoresistance (TMR) read heads comprise a pinned layer coupled to an antiferromagnet (AFM) layer. The TMR read heads further comprise a free layer separated from the pinned layer by a barrier layer
Data Source
AI summary
A tunnel magnetoresistance (TMR) read sensor having a tabbed AFM layer and an extended pinned layer and methods for making the same are provided. The TMR read sensor has an AFM layer recessed from the air bearing surface, providing a reduced shield-to-shield distance.