Segmented Read Sensor for High-Density Data Tracks
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Solution Overview
Problem
Magnetic read transducers in high-density disc drives face challenges with increased electronic and magnetic noise due to reduced size, affecting data-reproducing capabilities and requiring designs that are scaled to fit narrow data tracks, limiting their effectiveness.
Innovation Solution
The implementation of a read sensor with multiple free layers of differing widths, where the first free layer is segmented and the second is unsegmented, allowing for a bias current application that enhances read resolution and independence from data track dimensions, enabling multiple effective read widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the read transducer size is reduced to fit narrow data tracks in high-density disc drives, then the recording density and data transfer speed are improved, but the electronic and magnetic noise increases
Solution Approach 1:
The first free layer is divided into multiple segments separated by nonmagnetic material regions. This segmentation allows the sensor to read multiple adjacent tracks simultaneously while maintaining a larger overall sensor size, thereby reducing electronic and magnetic noise while still achieving high recording density through multi-track reading capability
Solution Approach 2:
The patent transitions from reading a single track to reading multiple tracks in parallel by extending the sensor width to span across multiple tracks. This dimensional expansion allows the sensor to maintain a larger area for reduced noise while achieving high effective recording density through simultaneous multi-track data acquisition
2Productivity
If the read transducer size is reduced to fit narrow data tracks, then the sensor can accommodate high-density recording, but the measurement precision deteriorates
Solution Approach 1:
The segmented first free layer enables independent or combined reading of multiple tracks, allowing the system to maintain high measurement precision by selecting appropriate reading modes (single track or multiple tracks) while accommodating high recording density through the expanded sensor footprint
Solution Approach 2:
The sensor is designed to perform multiple functions: it can read single tracks with high precision when needed, or read multiple tracks in parallel for high-density data acquisition. The segmented structure provides universal functionality that adapts to different recording density requirements while maintaining measurement precision
3Productivity
If the read transducer is scaled to fit narrow data tracks, then the device can operate in high-density environments, but the reliability decreases due to increased noise
Solution Approach 1:
The segmented structure with nonmagnetic material regions provides electrical and magnetic isolation between segments, reducing cross-talk and noise interference. This improves reliability by maintaining signal integrity even when reading multiple tracks in high-density environments
Solution Approach 2:
The nonmagnetic material regions act as intermediary elements that separate the segmented free layers, providing magnetic and electrical isolation. This intermediary structure reduces noise coupling between segments while allowing the sensor to maintain a larger overall size for improved reliability in high-density recording
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 allows for improved data-reproducing capabilities by reducing noise and enabling read sensors to maintain performance across varying track widths without being directly dependent on track dimensions, thus enhancing data transfer speeds and accuracy.
Implementation Method 1
The MR sensor has an electrical resistance that changes in response to an external magnetic field. This change in electrical resistance can be detected by processing circuitry in order to read magnetic data from the adjacent magnetic media.
Data Source
AI summary
An apparatus that includes a read sensor having a bearing surface and first and second free layers that are separated by an intermediate structure. The first FL includes multiple segments, with each segment having a width at the bearing surface. A sum of the widths of different ones of the multiple segments is a first width of the first FL. The second FL is unsegmented and has a second width at the bearing surface that is different from the first width of the first FL. The read sensor also includes a first terminal connected to a first one of the multiple segments of the first FL, and a second terminal connected to a second one of the multiple segments of the first FL. A third terminal is connected to the second FL. Control circuitry applies a bias current from either the first or second terminal to the third terminal.