Split Yoke TAMR Writer Head for Fast Rise Time
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Solution Overview
Problem
Current TAMR write head designs face challenges in achieving high data rates and area density capacity due to limitations in magnetic field strength, rise time, and optical power transfer, with existing designs either having slow rise times or being difficult to fabricate, and inducing optical power loss.
Innovation Solution
A split yoke design for the TAMR write head featuring a top yoke and main magnetic pole with a connector for flux closure, formed using conventional photolithography and etching techniques, which allows for strong magnetic fields and fast rise times while optimizing optical power transfer by minimizing electromagnetic coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a sloped main pole is introduced to minimize optical power loss, then optical power transfer is improved, but magnetic flux propagation becomes suboptimal and field rise time increases
Solution Approach 1:
The main pole is divided into multiple segments along its length, with each segment having a different slope angle. The distal portion has a steeper slope to minimize optical power loss, while the proximal portion has a gentler slope to maintain magnetic flux propagation efficiency and fast field rise time. This segmentation allows independent optimization of optical and magnetic performance characteristics.
2Speed
If a continuous piece of high-moment magnetic material is used for the sloped main pole, then fast field rise time is achieved, but fabrication complexity increases significantly
Solution Approach 1:
The main pole is constructed as multiple discrete segments rather than a continuous piece, making it compatible with standard photolithography and deposition processes. Each segment can be fabricated separately and then assembled, dramatically reducing fabrication complexity while maintaining the fast field rise time benefit of high-moment magnetic material.
Solution Approach 2:
The solution moves from attempting to create a complex 3D continuous sloped structure to a segmented approach that can be realized through 2D photolithography patterns followed by deposition and assembly, thereby simplifying the manufacturing process while achieving the same functional outcome.
3Loss of energy
If the main pole is constructed with multiple process steps to create a slope, then optical power loss is reduced, but the number of fabrication steps increases to hundreds
Solution Approach 1:
The main pole is divided into a small number of discrete segments (e.g., 3-5 segments) rather than requiring continuous sloping through hundreds of process steps. Each segment can be formed using standard photolithography and deposition, reducing the total process steps from hundreds to a manageable number while achieving the optical power loss reduction benefit.
4Ease of manufacture
If the top yoke and main magnetic pole are made as a single continuous structure, then fabrication is simplified, but magnetic flux propagation and field rise time are compromised
Solution Approach 1:
The top yoke and main magnetic pole are separated into distinct components rather than being made as a single continuous structure. This segmentation allows the main pole to be optimized for fast field rise time with high-moment magnetic material while the top yoke serves its flux return function, and both components can be fabricated using standard processes and assembled together.
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 split yoke design achieves faster rise times and higher magnetic field strengths comparable to existing designs with fewer process steps, maintaining higher signal-to-noise ratios at faster data rates and avoiding optical power loss, thus improving the recording medium's performance.
Implementation Method 1
a connector formed between the main magnetic pole and return pole, where the connector provides flux closure between the main magnetic pole and return pole
Implementation Method 2
optimizing optical power transfer by minimizing electromagnetic coupling
Implementation Method 3
allow the magnetic field from the writer head to polarize the magnetization of the magnetic grains of the media
Implementation Method 4
applying heat locally on the recording media to temporarily reduce its anisotropy
Data Source
AI summary
A write head configured for thermally assisted magnetic recording (TAMR) has a split-yoke design that allows the yoke and magnetic pole to be formed as planar layers while the split between left and right-side portions of the yoke and magnetic pole eliminate adverse coupling between the magnetic writing field and the optical near-field heating field. The planar design is easy to fabricate and provides rapid rise time and a strong magnetic field using fewer current-carrying coils than in the prior art.