Magnetic Sensor Extended Pinned Layer Bias Structure
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Solution Overview
Problem
As magnetic read sensors become smaller to increase data density, the stability of the free layer and pinned layer structures is compromised, necessitating a solution to maintain both stability and practical manufacturing processes.
Innovation Solution
A magnetic read sensor design featuring an extended pinned layer structure and shape-enhanced magnetic bias structure, with hard bias structures extending beyond the free layer stripe height and laterally tapering, improves pinning strength and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the read sensor size is reduced to increase data density, then data storage capacity is improved, but the stability of the free layer and pinned layer structures deteriorates
Solution Approach 1:
The pinned layer is extended in the vertical dimension (stripe height direction) beyond the free layer's termination point. This vertical extension provides additional pinning area and enhanced magnetic anisotropy without increasing the lateral footprint of the sensor, thereby maintaining small sensor size while improving layer stability through dimensional transformation.
Solution Approach 2:
The patent employs a composite structure combining the extended pinned layer with shape-enhanced magnetic bias structures. This composite design integrates multiple functional elements (pinned layer, free layer, bias structures) where the shape-enhanced bias structures provide additional magnetic field control and stability enhancement without requiring proportional increases in sensor dimensions.
2Quantity of substance
If the read sensor size is reduced to increase data density, then data storage capacity is improved, but manufacturing complexity increases
Solution Approach 1:
The sensor structure is segmented into distinct functional zones: the active sensing region where free and pinned layers interact, and the extended pinned layer region providing stability. This segmentation allows different portions of the structure to be optimized independently - the compact sensing region for high density and the extended region for stability - simplifying the manufacturing approach by clear functional differentiation.
Solution Approach 2:
The pinned layer exhibits local quality variation through its extended portion that terminates at a different stripe height than the free layer. This local structural differentiation concentrates the stability-enhancing function in specific regions (the extended pinned layer and bias structures) while keeping the main sensing region compact, thereby achieving high density without proportionally increasing overall manufacturing complexity.
3Reliability
If the pinned layer and hard bias structures are extended beyond the free layer stripe height, then pinning strength and reliability are improved, but structural complexity increases
Solution Approach 1:
The pinned layer and hard bias structures are extended in the vertical stripe height dimension beyond the free layer's termination point. This vertical extension provides additional pinning area and enhanced magnetic anisotropy without increasing the lateral footprint, thereby improving pinning reliability while maintaining structural compactness and avoiding excessive complexity.
Solution Approach 2:
The extended pinned layer and hard bias structures incorporate lateral tapering with curved or tapered profiles rather than abrupt terminations. This geometric smoothing reduces stress concentrations, improves magnetic field distribution, and simplifies manufacturing by providing gradual transitions that are easier to fabricate with standard lithography processes.
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 stability and reliability of both the pinned and free layers, maintaining robust pinning and biasing while allowing for practical construction and optimal performance in high-density data recording systems.
Implementation Method 1
shape enhanced bias structure... improves pinning strength and reliability
Implementation Method 2
Extending both the hard bias structure and the pinned layer structure beyond the free layer stripe height advantageously improves pinning strength
Implementation Method 3
first and second hard bias structures that are separated from the first and second sides of the sensor stack by first and second insulation layers
Implementation Method 4
A magnetoresistive sensor such as a Giant Magnetoresistive (GMR) sensor or a Tunnel Junction Magnetoresisive (TMR) sensor can be employed to read a magnetic signal from the magnetic media
Implementation Method 5
A magnetoresistive sensor such as a Giant Magnetoresistive (GMR) sensor or a Tunnel Junction Magnetoresisive (TMR) sensor can be employed to read a magnetic signal
Data Source
AI summary
A magnetic read sensor having an extended pinned layer structure and also having an extended free layer structure. The extended pinned layer structure and extended free layer structure both extend beyond the strip height of the free layer of the sensor to provide improved pinning strength as well as improved free layer biasing reliability and bias field strength.