Magnetic Shield for TDMR Sensor Alignment at Skew
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Solution Overview
Problem
Conventional magnetic recording transducers face challenges in achieving high recording densities and maintaining performance across varying skew angles, particularly in two-dimensional magnetic recording (TDMR) applications, where sensor misalignment and fabrication complexities arise.
Innovation Solution
The development of a magnetic recording read transducer with self-aligned read sensors, where the distance between sensors is set such that they remain centered on adjoining tracks at skew angles, utilizing multiple read sensors with specific layer configurations and magnetic bias structures to ensure accurate data sensing and noise accounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple read sensors are used in TDMR to enable higher recording densities, then recording density is improved, but sensor misalignment occurs at nonzero skew angles
Solution Approach 1:
The shield structure is designed to be skew-angle dependent, with its position and dimensions adjusted based on the operating skew angle. This dynamic adaptation allows the shield to compensate for skew effects and maintain proper sensor alignment across different radial positions on the disk, resolving the contradiction between high recording density and sensor alignment precision.
Solution Approach 2:
The shield's geometric parameters (position, width, height) are optimized as functions of the skew angle. By changing these parameters according to the operating conditions, the system maintains accurate sensor alignment while supporting multiple sensors for high-density recording, thus resolving the alignment issue without sacrificing recording capacity.
2Reliability
If sensors are moved to accommodate skew angles, then recording performance at nonzero skew is improved, but fabrication complexity increases
Solution Approach 1:
The shield acts as an intermediary element between the sensor array and the skew angle variation. Instead of directly adjusting sensor positions for each skew condition (which would increase fabrication complexity), the shield mediates the skew effect by providing a structured compensation mechanism that simplifies the overall fabrication process while maintaining recording performance.
Solution Approach 2:
The shield structure is pre-configured with specific geometric parameters that anticipate and compensate for skew angle effects before they occur during operation. This preliminary design approach avoids the need for complex post-fabrication adjustments or multi-configuration manufacturing, thereby reducing fabrication complexity while ensuring reliable recording performance across different skew conditions.
3Ease of manufacture
If conventional transducer structure is used, then fabrication is simpler, but performance degrades at higher recording densities
Solution Approach 1:
The transducer structure is segmented into distinct functional components: the shield element and the sensor array. This segmentation allows the shield to be designed and fabricated separately with optimized parameters for high-density recording, while the sensor array maintains a regular, easily manufacturable configuration. The segmented approach enables high recording density without sacrificing fabrication simplicity.
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 enhances the performance of the transducer by maintaining accurate data sensing across different skew angles and improving fabrication precision, thereby addressing the limitations of conventional transducers in TDMR applications.
Implementation Method 1
The magnetic bias structures 16 may be hard bias structures or soft bias structures. These magnetic bias structures are used to magnetically bias the sensor layer of the sensor 14.
Implementation Method 2
The read sensor 14 is typically a giant magnetoresistive (GMR) sensor or tunneling magnetoresistive (TMR) sensor.
Implementation Method 3
The free layer has a magnetization sensitive to an external magnetic field. Thus, the free layer functions as a sensor layer for the magnetoresistive sensor 14.
Data Source
AI summary
A method and system provide a magnetic transducer having an air-bearing surface (ABS). The method provides a first read sensor stack and defines a first read sensor in a stripe height direction from the first read sensor stack. The stripe height direction is perpendicular to the ABS. A shield is provided on the first read sensor stack and in a down track direction from the first read sensor stack. A second read sensor stack is provided. The shield is between the first read sensor and the second read sensor stack in the down track direction. Both the first read sensor and the second read sensor are defined from the first read sensor stack and from the second read sensor stack, respectively, in a cross-track direction. The cross-track direction is substantially perpendicular to the down track direction and substantially perpendicular to the stripe height direction.