Magnetic Sensor Pinned Layer Wing Design for Track Resolution
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Solution Overview
Problem
Magnetic read sensors face challenges in achieving high data density recording due to side reading phenomena and reduced pinning strength as sensors become smaller, necessitating improved side shielding and pinning mechanisms.
Innovation Solution
A magnetic sensor design featuring a magnetic pinned layer with laterally extending wing portions and tapered surfaces, combined with magnetic side shields that conform to the pinned layer's taper, enhances side shielding and pinning strength, optimizing data track resolution and sensor reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor size is reduced to achieve higher recording density, then the data track resolution is improved, but the pinning strength of the pinned layer deteriorates
Solution Approach 1:
The pinned layer is extended in the lateral dimension by adding wing portions that protrude beyond the sensor stack boundaries. This dimensional extension increases the pinned layer area and pinning strength without increasing the sensor stack footprint, thereby maintaining high data track resolution while improving pinning robustness.
Solution Approach 2:
The pinned layer is segmented into a central portion and lateral wing portions. The central portion maintains the original sensor stack configuration for optimal read signal, while the wing portions extend laterally to provide enhanced pinning. This segmentation allows independent optimization of read performance and pinning strength.
2Object-affected harmful factors
If conventional side shield structures are used, then side reading is suppressed, but data track resolution deteriorates at very high data densities
Solution Approach 1:
The side shields are configured with non-uniform thickness, being thicker at the leading end and thinner at the trailing end. This local quality variation optimizes the balance between side reading suppression and data track resolution, providing stronger shielding where needed while maintaining resolution where data is read.
Solution Approach 2:
The side shields exhibit asymmetric configuration relative to the sensor stack, with different thickness profiles at the leading and trailing ends. This asymmetric design allows differential suppression of side reading from adjacent tracks while preserving the read signal from the target track, optimizing data track resolution at high densities.
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
The novel sensor design effectively suppresses side reading and improves data track resolution at high densities while maintaining robust pinning, even at small sensor sizes, thereby enhancing recording performance and reliability.
Implementation Method 1
the novel pinned layer shape improves magnetic pinning of the pinned layer structure, thereby improving sensor reliability and robustness
Implementation Method 2
first and second magnetic side shield structures extending laterally from the first and second sides of the magnetic free layer structure... optimizes magnetic side shield effectiveness for improved data track resolution
Implementation Method 3
Magnetic reproducing heads utilizing the magnetoresistance effect of a multilayer film having ferromagnetic metal layers laminated with a nonmagnetic intermediary layer in between, or so-called giant magnetoresistance effect (hereafter, GMR)
Implementation Method 4
TMR (tunneling magnetoresistance effect) heads... appeared to be useful for obtaining high output by narrowing the track width and narrowing the gap
Data Source
AI summary
A magnetic sensor having improved pinned layer robustness for improved reliability and having improved side shielding for improved track resolution at very high data densities. The sensor has a pinned layer structure with laterally extending wing portions that become thicker with increasing distance from the air bearing surface and has a side shield structure has a thickness that decreases with increasing distance from the air bearing surface.