Magnetic Writer Pole Stray Field Control via Magneto-Elastic Anisotropy
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Solution Overview
Problem
Magnetic storage systems, such as hard disk drives, face issues with stray fields from writer heads that can unintentionally erase data, leading to reliability problems like main pole domain lock up and side track erasure, which existing technologies have not effectively addressed due to the complexity of three-dimensional structures and limitations in implementing magnetic anisotropy.
Innovation Solution
The solution involves enhancing magneto-elastic anisotropy by selecting specific materials and additives, combining them in an electrolyte solution, adding nitrogen, and using pulse plating to deposit thin films on wafers, followed by lapping to minimize stray fields, thereby controlling the orientation of magnetization and reducing domain lock up and side track erasure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional writer head structures are used, then manufacturing is simpler, but stray fields cause domain lock up and side track erasure
Solution Approach 1:
The patent changes the magnetic anisotropy parameter by introducing magneto-elastic anisotropy through controlled tensile stress in the writer pole material. This parameter change redirects the magnetization orientation to minimize stray fields, thereby reducing domain lock up and side track erasure while maintaining manufacturing feasibility
Solution Approach 2:
The patent employs composite material structures combining ferromagnetic materials with specific magneto-elastic properties. By selecting materials with appropriate magnetostriction coefficients and introducing tensile stress, the composite structure achieves enhanced control over magnetization orientation and stray field reduction
2Reliability
If magnetic anisotropy is enhanced to control stray fields, then reliability improves, but device complexity increases
Solution Approach 1:
Rather than complicating the structural design, the patent achieves reliability improvement by changing the magnetic parameter (anisotropy) through material selection and stress control. This approach enhances stray field control while maintaining relatively simple writer head structures
Solution Approach 2:
The patent replaces complex geometric or structural solutions with a physics-based approach using magneto-elastic effects. By substituting mechanical/structural complexity with controlled magnetic parameter changes, the patent achieves reliability improvement without proportionally increasing device complexity
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 approach effectively minimizes stray fields, reducing domain lock up and side track erasure issues, enhancing the reliability of magnetic storage systems by aligning magnetization in the preferred direction and maintaining high tensile stress, which improves the stability and performance of magnetic writer heads.
Implementation Method 1
depositing the combined solution as a thin film on a wafer using pulse plating
Implementation Method 2
enhancing the magnetic anisotropy to the preferred direction... utilizing the magneto-elastic anisotropy
Implementation Method 3
where the product of a magneto-striction of the materials for the magnetic feature and a tensile stress of the materials for the magnetic feature is a positive value
Data Source
AI summary
Systems and methods for controlling stray fields of a magnetic feature are provided. One such method can involve selecting a plurality of materials for a magnetic feature, selecting a plurality of additives, combining the plurality of materials for the magnetic feature and the plurality of additives in an electrolyte solution to form a combined solution, adding nitrogen to the combined solution, degassing the combined solution, depositing the combined solution as a thin film on a wafer using pulse plating, and lapping the thin film to form an edge of the magnetic feature. In several embodiments, the magnetic feature is a component of a magnetic transducer such as a writer pole, a reader shield, or a writer shield.