Magnetic Read Shield Flux Control for High Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic read sensors face difficulties in distinguishing stored information from noise as areal densities increase, leading to the need for enhanced sensitivity and resolution to prevent reading adjacent data.
Innovation Solution
The implementation of a reader stack with first and second read shields, each featuring a thin high permeability layer and a low permeability layer, along with geometric features at the air bearing surface, to control magnetic field flux lines and reduce interference from adjacent stored information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If areal densities increase to store more information, then storage capacity improves, but noise from adjacent stored information increases making it difficult to separately read information
Solution Approach 1:
The read head is segmented into multiple functional layers including first and second read shields with different permeability characteristics. The high permeability layer focuses flux lines while the low permeability layer prevents lateral spread, creating distinct functional zones that separate signal detection from noise rejection.
Solution Approach 2:
Different regions of the read head structure are assigned different magnetic permeability properties. The first read shield has high permeability to concentrate flux lines vertically, while the second read shield has low permeability to prevent horizontal flux spread, creating localized functional zones optimized for different aspects of signal detection.
2Measurement precision
If sensitivity and resolution of MR sensors are increased to read information at higher areal densities, then reading accuracy improves, but the sensors become more susceptible to noise from adjacent data
Solution Approach 1:
The dual-layer shield structure acts as an intermediary between the MR sensor and the magnetic medium. The high permeability layer serves as a flux concentrator that directs signal-bearing flux lines to the sensor, while the low permeability layer serves as a flux barrier that blocks noise from adjacent tracks, protecting the sensitive sensor without reducing its resolution.
3Reliability
If magnetic shields are added to the read head to prevent reading adjacent track information, then track isolation improves, but the complexity of the read head structure increases
Solution Approach 1:
The shielding function is merged with the structural framework of the read head. The first and second read shields are integrated into the existing layered architecture, combining mechanical support, flux management, and noise rejection functions into a unified structure rather than adding separate shield components.
4Ease of manufacture
If the read head structure is simplified to reduce manufacturing complexity, then ease of manufacture improves, but the ability to control magnetic field flux lines and reduce noise interference deteriorates
Solution Approach 1:
The invention controls flux lines by changing the magnetic permeability parameter of different layers rather than through complex geometric arrangements. The high permeability of the first shield and low permeability of the second shield create the desired flux control effect through material property selection, simplifying the manufacturing process while maintaining effective noise rejection.
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 effectively reduces PW50 values, enhancing readback resolution and preventing noise interference, thereby improving the ability to accurately read stored information without adjacent data contamination.
Implementation Method 1
a thin high permeability layer closest to the reader stack
Implementation Method 2
a low permeability layer to control magnetic field flux lines in a free layer of the reader stack
Data Source
AI summary
An apparatus that includes a first read shield and a second read shield and a reader stack between the first and second read shields. The first and second read shields each include a thin high permeability layer closest to the reader stack and a low permeability layer and/or a geometric feature to control magnetic field flux lines in a free layer of the reader stack.