Magnetic Write Head Notch Enhances Field Gradient
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Solution Overview
Problem
Current magnetic recording technologies face challenges in achieving high-density recording due to the need for narrower writers, which reduce the write field magnitude and gradient, while shorter bits require larger gradients without degrading the field magnitude, and existing solutions like MAMR are difficult to fabricate and require joint optimization of the writer and media.
Innovation Solution
The introduction of a write head with a magnetic DC-field-generation (DFG) layer, which includes a magnetic notch and a non-magnetic spacer, providing a spin-torque to align the DC component of the magnetization opposite to the gap field, enhancing the write field and gradient without requiring resonance with the magnetic layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the writer is narrowed to write narrower bits, then the bit width is reduced, but the write field magnitude and gradient are reduced
Solution Approach 1:
The patent introduces a magnetic notch with specific magnetic properties (different from the main pole material) localized at the pole tip region. This notch creates a concentrated magnetic field enhancement zone that provides high write field magnitude and gradient locally at the write gap, enabling narrow writer width while maintaining sufficient write field strength for high-density recording.
Solution Approach 2:
The write head employs a composite structure combining the main pole material with a magnetic notch material having different magnetic properties. This composite approach allows the magnetic notch to generate enhanced write field and gradient while the main pole provides the primary write field, achieving both narrow bit width and adequate write field magnitude simultaneously.
2Area of stationary object
If the writer is narrowed to increase track density, then the track width is reduced, but the write field magnitude and gradient are reduced
Solution Approach 1:
The magnetic notch creates a localized region of enhanced magnetic field gradient at the pole tip, concentrated at the write gap interface. This local field enhancement enables the narrow writer to achieve sufficient write field gradient for high track density while maintaining the reduced writer width required for narrow track spacing.
Solution Approach 2:
The magnetic notch introduces a vertical dimension to the magnetic field distribution by creating field enhancement in the depth direction at the pole tip. This dimensional approach allows the write head to achieve high gradient in the cross-track direction without increasing the lateral writer width, thus enabling high track density.
3Length of moving object
If shorter bits are written, then the bit length is reduced, but the write field gradient must be increased
Solution Approach 1:
The magnetic notch concentrates the write field gradient enhancement at the precise location of the write gap, creating a localized high-gradient zone. This focused gradient enhancement enables the writing of shorter bits by providing the necessary field gradient exactly where needed, without requiring the entire writer structure to be larger.
4Force
If MAMR is implemented, then the write field enhancement is achieved, but the fabrication difficulty increases and joint optimization of writer and media is required
Solution Approach 1:
The magnetic notch uses conventional magnetic materials and standard deposition techniques that are already成熟 in the industry, avoiding the need for complex spin-torque oscillator structures. This approach provides write field enhancement through a simpler, more manufacturable structure that does not require joint optimization of writer and media parameters.
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 solution provides a stable and easily fabricated write head with improved write field and gradient, enabling high-density magnetic recording without the need for joint optimization of the writer and media, resulting in smaller transition jitter and increased areal density capacity.
Implementation Method 1
providing a spin-torque to align the DC component of the magnetization opposite to the gap field
Implementation Method 2
magnetic DC-field-generation (DFG) layer
Data Source
AI summary
A write head for a data storage device comprises a main pole, a trailing shield, and a write-field enhancement structure disposed in a write gap between the main pole and the trailing shield. The write-field enhancement structure comprises a non-magnetic spacer, a non-magnetic layer, and a magnetic DC-field-generation (DFG) layer. The DFG layer is sandwiched between the non-magnetic layer and the non-magnetic spacer. The write head also includes at least one magnetic notch adjacent to at least one of the main pole or the trailing shield. The non-magnetic spacer is adjacent to a magnetic notch. Some embodiments include multiple magnetic notches. Also disclosed are data storage devices comprising such write heads.