Mirrored Antiferromagnetically Coupled Shields for Magnetic Transducers
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Solution Overview
Problem
Conventional magnetic recording read transducers face performance issues due to the nanostructure of shields, which can adversely affect the read sensor, especially at higher recording densities and smaller track widths, leading to noise and performance degradation.
Innovation Solution
The implementation of mirrored antiferromagnetically coupled (AFC) shields, where the second AFC shield is a mirror image of the first AFC shield in terms of ferromagnetic layer thickness and saturation magnetization, with nonmagnetic spacer layers configured for antiferromagnetic coupling, reduces noise and disturbances from internal and external fields, thereby improving transducer performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional shields are used in magnetic recording read transducers, then the transducer can function at basic recording densities, but the shields adversely affect sensor performance at higher recording densities and smaller track widths due to their nanostructure
Solution Approach 1:
The patent applies asymmetry by using shields with different magnetization directions relative to the sensor. Specifically, one shield has magnetization parallel to the sensor magnetization while the other has antiparallel magnetization, creating an asymmetric configuration that optimizes noise cancellation at high recording densities
Solution Approach 2:
The patent changes the magnetic parameters of the shields by introducing different saturation magnetizations and coercive forces. The first shield has higher saturation magnetization and coercive force compared to the second shield, allowing optimization of the magnetic field distribution and noise characteristics for high-density recording
2Ease of manufacture
If shield structures are simplified for easier manufacture, then manufacturing complexity decreases, but the shields cannot effectively cancel magnetic disturbances from internal and external fields
Solution Approach 1:
The patent uses composite magnetic shield structures consisting of multiple layers with different magnetic properties. Each shield comprises soft magnetic material layers with specific permeability and coercivity characteristics, creating a composite structure that effectively cancels magnetic disturbances while maintaining manufacturability through standard deposition techniques
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 symmetry between the AFC shields results in reduced magnetic noise and improved performance at higher recording densities and smaller track widths, enhancing the overall performance of the magnetic transducer by minimizing disturbances from internal and external fields.
Implementation Method 1
The nonmagnetic spacer layer is configured such that the first and second ferromagnetic layers are coupled antiferromagnetically
Implementation Method 2
The symmetry between the AFC shields results in reduced magnetic noise and improved performance at higher recording densities
Data Source
AI summary
A method provides a magnetic transducer including a first antiferromagnetically coupled (AFC) shield, a second AFC shield and a read sensor between the first and second AFC shields. The first AFC shield includes first and second ferromagnetic layers and a first nonmagnetic spacer layer between the first and second ferromagnetic layers. The first and second ferromagnetic layers have first and second saturation magnetizations and first and second thicknesses, respectively. The second ferromagnetic layer is between the read sensor and the first ferromagnetic layer. The second AFC shield includes third and fourth ferromagnetic layers and a second nonmagnetic spacer layer between the third and fourth ferromagnetic layers. The third ferromagnetic layer is between the read sensor and the fourth ferromagnetic layer. The third and fourth ferromagnetic layers have third and saturation magnetizations and third and fourth thicknesses, respectively. The second AFC shield is a mirror image of the first AFC shield.