HAMR Head Solid Immersion Mirror for Thermal Degradation Control
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Solution Overview
Problem
Heat-assisted magnetic recording (HAMR) heads in hard disk drives face issues of material degradation due to excess thermal exposure and degradation of write capability from extraneous magnetic fields, which reduce their lifetime and performance.
Innovation Solution
Incorporating a solid immersion mirror made of a thermally robust metal with a melting temperature of at least 1500°C, disposed proximal to the near-field transducer, to improve localized surface plasmon coupling efficiency, reduce laser power requirements, and provide magnetic shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional materials are used in the solid immersion mirror, then manufacturing cost may be lower, but thermal degradation and defect formation occur under excess thermal exposure
Solution Approach 1:
The patent changes the material parameter from conventional metals to thermally robust metals with melting temperatures of at least 1500°C. This parameter change enables the solid immersion mirror to withstand the high thermal exposure in HAMR operations without degradation or defect formation, directly resolving the contradiction between reliability and temperature resistance.
Solution Approach 2:
The patent employs composite material structures combining thermally robust metals with magnetic materials in the solid immersion mirror. This composite approach simultaneously achieves thermal stability and magnetic shielding functionality, resolving the contradiction by integrating multiple material properties into a unified structure that withstands thermal exposure while maintaining operational reliability.
2Reliability
If a thermally robust metal is used in the solid immersion mirror, then thermal degradation is reduced, but material selection and manufacturing complexity increase
Solution Approach 1:
The patent establishes a clear material selection criterion based on the melting temperature parameter (at least 1500°C), which simplifies the manufacturing process by providing a definitive threshold for selecting thermally robust metals. This parameter-based approach resolves the contradiction by transforming complex material selection into a straightforward specification requirement.
3Productivity
If the solid immersion mirror is extended closer to the media-facing surface, then optical coupling and LSP generation are improved, but deformation under thermal exposure may increase
Solution Approach 1:
The patent uses composite materials combining thermally robust metals with magnetic materials to create a solid immersion mirror that can be positioned closer to the media-facing surface. The thermally robust metal component resists thermal deformation, enabling the structure to maintain its position and achieve improved optical coupling without suffering from thermal-induced deformation.
Solution Approach 2:
The patent changes the thermal stability parameter of the solid immersion mirror materials, enabling the structure to maintain dimensional stability at elevated temperatures. This parameter change allows the mirror to be extended closer to the media-facing surface where optical coupling is enhanced, without compromising structural integrity against thermal deformation.
4Object-affected harmful factors
If magnetic materials are included in the solid immersion mirror, then shielding against extraneous magnetic fields is improved, but material complexity increases
Solution Approach 1:
The patent merges the optical mirror function with magnetic shielding function into a single integrated solid immersion mirror structure. By combining thermally robust metals with magnetic materials, the design eliminates the need for separate magnetic shielding components, reducing overall device complexity while achieving magnetic field shielding against extraneous fields from adjacent tracks.
Solution Approach 2:
The solid immersion mirror is designed with multi-functionality, simultaneously serving as an optical element for LSP generation and a magnetic shield against extraneous fields. This universal design approach resolves the contradiction by integrating multiple functions into one component, achieving magnetic field shielding without increasing overall 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
The solution extends the lifetime of the HAMR head by reducing thermal degradation and deformation, enhances optical coupling, and improves write capability by blocking scattered photons and shielding against extraneous magnetic fields.
Implementation Method 1
The laser emits electromagnetic radiation that resonates with free electrons of the NFT to excite localized surface plasmons (LSPs) on the NFT
Implementation Method 2
blocking scattered incident photons from a source (e.g., the laser)
Implementation Method 3
blocking photons from reaching external surfaces such as a surface of a magnetic disk
Implementation Method 4
reducing reflection from surfaces such as a media-facing surface
Implementation Method 5
blocking scattered incident photons from a source (e.g., the laser), by blocking photons from reaching external surfaces such as a surface of a magnetic disk, and/or by reducing reflection from surfaces such as a media-facing surface
Data Source
AI summary
A heat-assisted magnetic recording head includes a near-field transducer, a waveguide, and a solid immersion mirror. The near-field transducer is configured to focus and emit an optical near-field. The waveguide is configured to receive electromagnetic radiation and propagate the electromagnetic radiation toward and proximal to the near-field transducer. The solid immersion mirror is disposed proximal to the near-field transducer and along a media-facing surface of the heat-assisted magnetic recording head. The solid immersion mirror includes a first segment and a second segment disposed on opposite sides of the near-field transducer relative to a cross-track dimension of the heat-assisted magnetic recording head. The solid immersion mirror includes a thermally robust metal having a melting temperature of at least 1500 degrees Celsius. The thermally robust metal is a primary material of the solid immersion mirror.