Recessed Antiferromagnetic Layer for Narrow Read-Gap Head
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Solution Overview
Problem
The challenge is to reduce the read gap thickness of magnetic read heads while maintaining reliability, as existing sensors are sensitive to magnetic disturbances and prone to amplitude flipping due to reduced antiferromagnetic layer thickness or its removal.
Innovation Solution
A magnetic read head design with a recessed antiferromagnetic layer that provides a pinning field, reducing the read gap thickness by the thickness of the antiferromagnetic layer and preventing amplitude flipping, by positioning it above or below the pinned layer structure and extending to the air bearing surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the antiferromagnetic layer thickness is reduced or removed to reduce read gap, then the read gap thickness is reduced, but the sensor becomes sensitive to magnetic disturbances and prone to amplitude flipping
Solution Approach 1:
The patent positions the antiferromagnetic layer in a recessed configuration below the pinned layer structure, utilizing the vertical dimension to separate the read gap reduction function from the pinning function. This allows the read gap to be reduced while the antiferromagnetic layer remains in place to provide stable pinning, preventing amplitude flipping.
Solution Approach 2:
The sensor structure is segmented into distinct functional regions: the pinned layer structure extending to the air bearing surface for read gap reduction, and the recessed antiferromagnetic layer for providing pinning field. This segmentation allows each component to optimize its specific function without compromising the other.
2Productivity
If the read gap thickness is reduced to increase data density, then data recording density is improved, but the sensor sensitivity to external magnetic fields may be compromised
Solution Approach 1:
By positioning the antiferromagnetic layer in a recessed configuration below the pinned layer, the patent maintains the pinned layer's extension to the air bearing surface, ensuring that the read gap remains reduced for high data density while the antiferromagnetic layer continues to provide stable pinning for sensitive magnetic field detection.
Solution Approach 2:
The pinned layer structure is designed with local quality variations, extending to the air bearing surface in the read gap region while the antiferromagnetic layer is positioned in a recessed area. This local differentiation allows the pinned layer to provide sensitive magnetic field detection at the critical read gap location while the recessed antiferromagnetic layer provides stable pinning.
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 enhances the reliability and performance of magnetic read heads by reducing the read gap thickness without compromising sensitivity to external magnetic fields, thereby improving data recording density.
Implementation Method 1
The recessed antiferromagnetic layer may be disposed above or below the pinned layer structure and provides a pinning field to prevent amplitude flipping in head operation
Implementation Method 2
The magnetization of the pinned layer is pinned perpendicular to the ABS and the magnetic moment of the free layer is located parallel to the ABS, but free to rotate in response to external magnetic fields
Implementation Method 3
the magnetic moment of the free layer is located parallel to the ABS, but free to rotate in response to external magnetic fields
Data Source
AI summary
The embodiments of the present invention relate to a magnetic read head with pinned layers extending to the ABS of the read head and in contact with an antiferromagnetic layer that is recessed in relation to the ABS of the read head. The recessed antiferromagnetic layer may be disposed above or below the pinned layer structure and provides a pinning field to prevent amplitude flipping in head operation. In these embodiments of the present invention, the read gap of the sensor, that is the distance between the highly permeable, magnetically soft upper and lower shield layers at the ABS, is reduced by the thickness of the antiferromagnetic layer.