STO Reader Side Shields for Flux Absorption
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Solution Overview
Problem
The miniaturization of HDD components for increased recording density is hindered by the discrepancy between physical reader track width and magnetic read width due to stray magnetic flux, and implementing side shields to absorb this flux complicates sensor stabilization by potentially reducing available magnetic field for sensor operation.
Innovation Solution
A spin torque oscillator (STO) sensor with highly magnetically permeable side shields that are exchange and electrically decoupled from the sensor, allowing for the absorption of stray flux without affecting sensor performance, and optionally incorporating a hard bias at the back edge to maintain stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If side shields are implemented to absorb stray flux, then signal-to-noise ratio is improved, but sensor stabilization is compromised due to reduced available magnetic field
Solution Approach 1:
The patent introduces a magnetically permeable material as an intermediary component positioned between the side shields and the sensor. This intermediary absorbs the stray magnetic flux from adjacent tracks before it reaches the sensor, protecting the sensor's magnetic field stability while still improving the signal-to-noise ratio by reducing magnetic interference from adjacent tracks
2Productivity
If component dimensions are reduced for higher recording density, then areal density is improved, but fabrication constraints increase due to discrepancy between physical track width and magnetic read width
Solution Approach 1:
The patent addresses the track width discrepancy by adding side shields that extend in the cross-track dimension. These shields absorb stray flux from adjacent tracks, effectively increasing the magnetic read width to match the physical track width even as the overall device dimensions are reduced for higher recording density
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 configuration enables the fabrication of smaller magnetic heads with improved signal-to-noise ratio and larger physical track width without compromising sensor stability, facilitating the miniaturization necessary for higher recording densities.
Implementation Method 1
one or more of the at least one shield comprises a highly magnetically permeable material that is exchange decoupled and electrically decoupled from the STO sensor
Implementation Method 2
spin torque oscillator (STO) sensor positioned above the first shield
Data Source
AI summary
In one embodiment, a magnetic head includes a first shield; a spin torque oscillator (STO) sensor positioned above the first shield, the STO sensor comprising a reference layer and a free layer positioned above the reference layer; and at least one shield positioned in a plane that is parallel with a media-facing surface of the STO sensor, the plane also intersecting the STO sensor, wherein one or more of the at least one shield comprises a highly magnetically permeable material that is exchange decoupled and electrically decoupled from the STO sensor. Other magnetic heads, systems, and methods for producing the magnetic heads are described according to more embodiments.