Au Alloy Plasmonic Underlayer for HAMR Thermal Management
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Solution Overview
Problem
Conventional heat sink layers in heat-assisted magnetic recording (HAMR) media conduct heat both vertically and laterally, limiting track density and data bit size due to lateral thermal spreading, and are often made from soft metallic materials that are not mechanically durable enough for HDD technology.
Innovation Solution
A plasmonic underlayer comprising gold (Au) alloys with immiscible alloying components such as Rh, Ni, W, or Mo is used, which provides high thermal and electrical conductivity while maintaining morphological stability at high temperatures, thereby confining heat and enhancing thermal gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heat sink layers are used to conduct heat away from the recording layer, then thermal management is improved, but lateral thermal spreading occurs which limits track density and data bit size
Solution Approach 1:
The patent applies local quality by creating vertical heat conduction channels through alternating layers of high thermal conductivity materials (e.g., Ru, Rh, Ir, Cu, Ag, Al) and low thermal conductivity materials (e.g., Ta, W, Mo, Hf, Pt, Pd, oxides, nitrides). This layered structure enables heat to be conducted away vertically from the recording layer while blocking lateral heat spread, thus improving thermal management without compromising track density
Solution Approach 2:
The heat sink layer is segmented into multiple alternating layers of high and low thermal conductivity materials. This segmentation creates a thermal management structure that selectively conducts heat vertically while blocking lateral heat flow paths, resolving the contradiction between thermal management and track density
2Productivity
If conventional metallic materials with high thermal conductivity such as pure Cu, Ag, Al are used, then thermal conductivity is improved, but mechanical durability and surface roughness are insufficient
Solution Approach 1:
The patent employs composite materials by combining high thermal conductivity metals (Cu, Ag, Al) with low thermal conductivity but mechanically durable materials (Ta, W, Mo, Hf, Pt, Pd, oxides, nitrides) in alternating layers. This composite structure provides both the required thermal conductivity for heat management and the mechanical durability needed for HDD operation, resolving the contradiction between thermal performance and reliability
Solution Approach 2:
The patent changes the thermal conductivity parameter distribution within the heat sink layer by using alternating high and low thermal conductivity materials. This parameter variation allows the structure to achieve effective heat conduction while the mechanically durable low-conductivity layers provide structural support and surface stability
3Power
If the magnetic media is heated to high temperatures during writing, then the effective coercivity is lowered enabling data writing, but thermal destabilization of written information occurs
Solution Approach 1:
The patent extracts heat rapidly from the heated recording region by introducing a heat sink layer with vertical heat conduction channels directly beneath the recording layer. This extracted heat is conducted away vertically through the alternating high-conductivity/low-conductivity layer structure, enabling the media to be heated to high temperatures for writing while preventing thermal destabilization of written information through rapid cooling
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 Au alloy plasmonic underlayer achieves improved thermal stability and conductivity, allowing for higher track and pitch densities in HAMR recording by minimizing lateral heat transfer and maintaining structural integrity, thus enhancing the reliability and performance of HAMR heads and media.
Implementation Method 1
A plasmonic underlayer comprising gold (Au) alloys with immiscible alloying components such as Rh, Ni, W, or Mo is used, which provides high thermal and electrical conductivity while maintaining morphological stability at high temperatures, thereby confining heat and enhancing thermal gradients
Implementation Method 2
HAMR recording employs heat to lower the effective coercivity of a localized region on the magnetic media surface and write data within this heated region. Heating of the media surface has been accomplished by a number of techniques such as focused laser beams or near field optical sources
Data Source
AI summary
According to one embodiment, a magnetic medium includes a plasmonic underlayer having an Au alloy, where the Au alloy includes one or more alloying components that are substantially immiscible in Au; and a magnetic recording layer above the plasmonic underlayer. According to another embodiment, a magnetic medium, includes a multilayered plasmonic underlayer; and a magnetic recording layer above the multilayered plasmonic underlayer.