Extended Pinned Layer Magnetic Sensor Gap Spacing Reduction
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Solution Overview
Problem
The existing magnetic data recording technologies face limitations in reducing gap spacing of magnetoresistive sensors, which hinders the increase in data density due to the physical constraints and the need for thick antiferromagnetic layers that contribute to gap spacing.
Innovation Solution
The magnetic read sensor employs an extended pinned layer structure with an antiferromagnetic layer stitched only beyond the first stripe height, avoiding contribution to gap spacing and enhancing pinning stability through exchange coupling, thereby allowing for reduced gap spacing without compromising antiferromagnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick antiferromagnetic layer is used to provide useful anti-ferromagnetic properties and exchange coupling with the pinned layer, then the pinning stability is improved, but the gap spacing increases significantly
Solution Approach 1:
The sensor structure is divided into two distinct regions: a first region containing the free layer and read pole for data reading, and a second region extending beyond the first stripe height containing the pinned layer and antiferromagnetic layer for stable pinning. This segmentation allows the antiferromagnetic layer to be positioned where it does not contribute to gap spacing while maintaining its stabilizing function.
Solution Approach 2:
The pinned layer and antiferromagnetic layer are extended in the vertical dimension beyond the first stripe height, utilizing the second region that extends to a greater second stripe height. This dimensional extension moves the antiferromagnetic layer out of the critical gap spacing region while preserving its exchange coupling function with the pinned layer.
2Quantity of substance
If the gap spacing of the sensor is reduced to increase data density, then the data density is improved, but the physical limitations of layer structure prevent further reduction
Solution Approach 1:
By segmenting the sensor into functional regions with the pinned layer and antiferromagnetic layer isolated in the second region beyond the first stripe height, the design eliminates unnecessary layers from the gap spacing region, enabling further gap spacing reduction and increased data density.
Solution Approach 2:
The stripe heights of the free layer and pinned layer are differentiated, with the pinned layer extending to a greater second stripe height. This parameter change optimizes the vertical positioning of layers to minimize gap spacing while maintaining all necessary magnetic properties and functions.
3Reliability
If the pinned layer is extended beyond the first stripe height to stitch with the antiferromagnetic layer, then the pinning stability is enhanced, but the device complexity increases
Solution Approach 1:
The structure is segmented into two functional regions that can be manufactured using standard photolithography and deposition processes. The first region handles reading operations while the second region provides stable pinning, allowing complex magnetic functionality to be achieved through spatial segmentation rather than complex material structures.
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 significantly reduces gap spacing, improving data density and the robustness of the sensor by eliminating the antiferromagnetic layer's contribution to gap spacing while maintaining necessary antiferromagnetic properties, thus enhancing the reliability and efficiency of data recording.
Implementation Method 1
a layer of antiferromagnetic material formed on and exchange coupled with the pinned layer structure only in a region beyond the first stripe height
Implementation Method 2
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. The magnetoresistive sensor has an electrical resistance that changes in response to an external magnetic field.
Implementation Method 3
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.
Data Source
AI summary
A magnetic sensor having a novel pinning structure resulting in a greatly reduced gap spacing. The sensor has a magnetic free layer structure that extends to a first stripe height and a magnetic pinned layer structure that extends to a second stripe height that is longer than the first stripe high. A layer of anti-ferromagnetic material is formed over the pinned layer structure in the region beyond the first stripe height location. In this way, the antiferromagnetic layer is between the pinned layer and the second or upper shield and does not contribute to gap spacing.