Bullet-Shaped Bottom Shield for Magnetic Read Head Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic read heads in data storage systems face instability and noise due to stray magnetic fields, leading to errors in readback operations, particularly when domain walls interact with small shield dimensions and unfavorable domain states.
Innovation Solution
A bullet-shaped bottom shield with one end rectangular and the other formed by the intersection of arcs is introduced, providing a stable domain configuration and increased robustness against stray fields, compatible with trilayer reader designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If small shield dimensions are used in magnetic read heads, then device size is reduced, but stability deteriorates due to domain wall interactions and stray magnetic fields
Solution Approach 1:
The shield is designed with an asymmetric geometry featuring a curved end formed by the intersection of arcs rather than a symmetric rectangular shape. This asymmetric configuration creates favorable domain states and stabilizes domain wall positions, preventing unwanted domain wall interactions while maintaining compact dimensions. The curved geometry fundamentally changes the magnetic domain structure compared to conventional symmetric shields.
Solution Approach 2:
The shield incorporates a localized curved region at one end (formed by arc intersection) while maintaining other structural regions. This local geometric modification targets specific domain wall interaction problems at the shield end without requiring complete redesign of the entire shield structure, achieving stability improvement in a focused manner.
2Device complexity
If shield dimensions are reduced, then device complexity is lowered, but noise increases due to stray magnetic field interference
Solution Approach 1:
The asymmetric curved-end geometry inherently suppresses stray magnetic fields by creating favorable flux closure patterns. The curved arc intersection design directs magnetic flux more effectively, reducing stray field leakage and associated noise without adding complex shielding structures or multiple components.
Solution Approach 2:
The shield end is designed with curved surfaces formed by intersecting arcs rather than sharp rectangular edges. This curvature promotes smoother magnetic flux distribution and reduces field concentration at corners, thereby minimizing stray magnetic fields and associated noise while maintaining structural simplicity.
3Ease of manufacture
If conventional rectangular shield design is used, then manufacturing is simplified, but predictability deteriorates due to unfavorable domain states
Solution Approach 1:
The curved end geometry formed by arc intersection, while more complex than a rectangle, creates fundamentally more predictable magnetic domain states. The curvature ensures favorable domain wall anchoring and consistent flux patterns, making read operations more reliable and predictable compared to conventional rectangular shields with their problematic corner domains.
Solution Approach 2:
The curved arc intersection design at the shield end promotes consistent and predictable magnetic flux distribution. This curvature eliminates the unfavorable domain states that occur at sharp rectangular corners, ensuring repeatable and predictable read operation behavior while remaining manufacturable through standard fabrication processes.
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 bullet-shaped shield design enhances predictability and stability in magnetic read operations, reducing noise and errors by effectively anchoring domain walls and maintaining flux closure, while maintaining permeability and compatibility with trilayer designs.
Implementation Method 1
maintaining flux closure
Implementation Method 2
effectively anchoring domain walls
Implementation Method 3
a magnetoresistive (MR) sensor for retrieving magnetically encoded information
Implementation Method 4
Magnetic flux from the surface of the disc causes rotation of the magnetization vector
Implementation Method 5
causes a change in electrical resistivity of the MR sensor
Data Source
AI summary
An apparatus disclosed herein comprises a reader structure having a sensor stack and a bottom shield having a first end and a second end on opposite sides of the bottom shield in a cross-track direction, wherein the first end is formed by intersection of arcs. In one implementation, the apparatus disclosed herein the sensor has a bottom shield having a bullet shape with a first end along a cross-track direction being rectangular and a second end along the cross-track direction being formed by an intersection of arcs.