Multilayer Near-Field Emitter for HAMR Head Thermal Management
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Solution Overview
Problem
The generation and condensation of localized surface plasmons in near-field transducers for heat-assisted magnetic recording heads lead to excessive heating and potential degradation of components, reducing the performance and lifespan of hard disk drives.
Innovation Solution
A multilayer near-field emitter with layers of different materials, including a metal with a higher optical extinction coefficient, is used to repel electric fields and improve near-field confinement, reducing heating and enhancing the thermal gradient, thereby extending the lifespan and increasing the areal density capability of the HAMR head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional near-field transducer is used to generate localized surface plasmons, then data writing capability is achieved, but excessive heating occurs causing component degradation and reduced lifespan
Solution Approach 1:
The near-field emitter is divided into multiple layers (first layer, second layer, third layer) with different materials and optical extinction coefficients. This segmentation allows different layers to perform specialized functions: the first layer with high extinction coefficient repels electric fields to reduce heating, while other layers manage near-field emission, thereby solving the contradiction between data writing capability and excessive heating.
Solution Approach 2:
Different layers of the near-field emitter are assigned different material properties and optical extinction coefficients tailored to specific functional requirements. The first layer uses material with high extinction coefficient for electric field repulsion and heating reduction, while subsequent layers use materials optimized for near-field emission. This local quality differentiation resolves the contradiction by optimizing each layer's properties for its specific function.
2Reliability
If near-field energy is not well confined, then heating is reduced, but areal density capability decreases
Solution Approach 1:
The near-field emitter is segmented into multiple layers with progressively different optical extinction coefficients. This segmentation enables the structure to simultaneously achieve good near-field confinement (for high areal density) and controlled heating (for reliability), as each layer contributes differently to the overall electromagnetic field distribution and energy confinement.
Solution Approach 2:
The near-field emitter uses composite material structure with multiple layers of different materials having different optical extinction coefficients. This composite approach allows the system to achieve both strong near-field confinement (improving areal density capability) and controlled thermal management (reducing excessive heating), thereby resolving the contradiction between these two 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 reduces heating in the near-field transducer, improves the reliability and lifespan of the HAMR head, and increases the areal density capability by better confining the near-field energy, allowing for more stable and densely packed data storage.
Implementation Method 1
Including a metal with a higher extinction coefficient in one layer (e.g., an electric field barrier layer) may repel electric fields from the layer and reduce electric field penetration into the NFT
Implementation Method 2
providing a layer with a metal having a high extinction coefficient near an emitting region of the multilayer near-field emitter may provide better confinement of an emitted near-field, potentially increasing the thermal gradient of the emitted near-field
Implementation Method 3
The process of generating and condensing localized surface plasmons (LSPs) on the NFT to produce the hot spot
Implementation Method 4
A recording head of a HAMR HDD typically includes a laser, a near-field transducer (NFT) configured to briefly heat a small hot spot on a surface of a magnetic disk
Data Source
AI summary
A heat-assisted magnetic recording head includes a near-field transducer including a plasmonic disk and a multilayer near-field emitter. The multilayer near-field emitter is configured to produce a hot spot on a proximal magnetic disk. The multilayer near-field emitter is disposed in a down-track direction relative to and coupled to the plasmonic disk.