Tapered Magnetic Write Pole for HAMR Data Density
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Solution Overview
Problem
Current magnetic write transducers in heat-assisted magnetic recording (HAMR) devices face limitations in achieving high areal data density due to relatively low magnetic field strength, which is affected by the superparamagnetic effect and thermally-induced data errors.
Innovation Solution
A magnetic write transducer design featuring a plasmonic gap waveguide with offset substrate-parallel sides and tapered write pole sections, coupled with a near-field transducer that enhances magnetic field strength by concentrating optical energy into a hotspot, allowing for increased areal data density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional magnetic write transducers are used, then the device structure is simple, but the magnetic field strength is insufficient for high areal data density
Solution Approach 1:
The write transducer is divided into multiple pole sections (first write pole section, second write pole section, third write pole section) with different geometries and magnetic moment characteristics. Each section contributes differently to the magnetic field generation, allowing optimization of field strength while managing structural complexity through functional segmentation.
Solution Approach 2:
The patent employs composite magnetic pole structures with different materials having varying magnetic moments. The first write pole section uses high-moment material while other sections use lower-moment materials, creating a composite structure that optimizes magnetic field strength. This material composition strategy enables achieving higher effective magnetic field strength (28% increase) without requiring uniform high-moment material throughout the entire structure.
2Strength
If the write pole extends close to the media surface, then the magnetic field strength increases, but the risk of head-disk contact and data errors increases
Solution Approach 1:
Different pole sections have different extension distances from the media surface. The first write pole section extends a first distance, the second write pole section extends a second distance (at least 1/5 of the first distance), and the third write pole section extends a third distance. This local variation in geometry allows the magnetic field to be concentrated effectively while maintaining adequate spacing to prevent head-disk contact and reduce data errors.
Solution Approach 2:
The patent optimizes the geometric parameters of each pole section, including extension distances and tapered tip dimensions. By carefully controlling these parameters, the magnetic field strength is enhanced (28% increase in effective field, 33% increase in perpendicular field) while maintaining reliable operating clearance between the transducer and recording media.
3Productivity
If high magnetic field strength is achieved, then data density increases, but thermal effects and data errors increase
Solution Approach 1:
The patent employs heat-assisted magnetic recording (HAMR) technology, utilizing controlled thermal effects to assist the magnetic writing process. By applying localized heat to the recording media, the magnetic coercivity is temporarily reduced, enabling higher data density recording. The optimized pole structure enhances the magnetic field strength (28% increase in effective field) which works synergistically with the thermal assistance to achieve high areal data density while managing thermal effects through controlled application.
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 design achieves a 28% increase in effective magnetic field strength and 33% increase in perpendicular field strength, reducing data errors and improving data density, while maintaining low temperatures and high performance.
Implementation Method 1
A magnetic write transducer design featuring a plasmonic gap waveguide with offset substrate-parallel sides and tapered write pole sections, coupled with a near-field transducer that enhances magnetic field strength by concentrating optical energy into a hotspot
Implementation Method 2
A magnetic transducer, which includes a magnetic write pole, applies a magnetic field to the hotspot, locally changing magnetic orientation within the hotspot
Data Source
AI summary
A recording head has a magnetic write transducer proximate a side of a plasmonic gap waveguide. The magnetic write transducer has a first write pole section that tapers in a crosstrack direction and downtrack direction to form a tapered tip. The first write pole section includes a high-moment, seed layer on one side. A second write pole section is coupled to the first write pole section. The second write pole section extends a second distance away from the media-facing surface less than that of the first write pole section. A tip of the second write pole section is tapered in the crosstrack and downtrack directions.