HAMR Medium Thermal Barrier Layer for Laser Current Reduction
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Solution Overview
Problem
In heat-assisted magnetic recording (HAMR) media, optimizing the thermal conductivity of the MgO seed/thermal barrier layer is crucial to prevent excessive heat distribution, which requires high laser power or lateral heat spreading that can overwrite adjacent data tracks.
Innovation Solution
A multilayered heat-sink structure is introduced, comprising a first heat-sink layer and a RuAl—X thermal barrier layer, with the RuAl—X layer selected from C and oxides of Si, Ti, W, Zr, and Hf, to facilitate heat transfer away from the FePt recording layer, reducing the required laser current and improving magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the thermal conductivity of the MgO seed/thermal barrier layer is increased to prevent heat distribution, then heat confinement to the recording layer is improved, but lateral heat spreading occurs that can overwrite adjacent data tracks
Solution Approach 1:
The heat-sink layer is divided into multiple segments (first heat-sink layer, second heat-sink layer) separated by thermal barrier layers. This segmentation allows heat to be dissipated in a controlled manner through multiple pathways while preventing lateral heat spread to adjacent tracks, resolving the contradiction between heat confinement and preventing harmful heat distribution.
Solution Approach 2:
Thermal barrier layers (RuAl—X layers) are introduced as intermediary elements between the heat-sink layers and the MgO seed layer. These intermediary layers have controlled thermal conductivity that allows them to mediate heat flow, enabling vertical heat dissipation while blocking lateral heat spread, thus resolving the contradiction between heat confinement and preventing harmful heat distribution.
2Loss of energy
If a single heat-sink layer is used to transfer heat away from the FePt recording layer, then heat dissipation is improved, but excessive laser current is required
Solution Approach 1:
The heat-sink function is segmented across multiple layers (first heat-sink layer, thermal barrier layer, second heat-sink layer) rather than relying on a single thick layer. This segmentation creates multiple heat dissipation pathways that are more efficient, reducing the total laser current required to achieve the necessary temperature for recording while maintaining effective heat dissipation.
Solution Approach 2:
The patent uses a composite multilayer structure combining different materials with different thermal properties (heat-sink materials like Cu/Au/Ag with thermal barrier materials like RuAl—X). This composite structure optimizes heat dissipation efficiency while reducing the energy input required, resolving the contradiction between effective heat dissipation and laser current consumption.
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 multilayered heat-sink structure reduces the necessary laser current by 10% and slightly enhances magnetic properties, while preventing heat-induced overwriting of adjacent data tracks.
Implementation Method 1
A multilayered heat-sink structure is introduced, comprising a first heat-sink layer and a RuAl—X thermal barrier layer, with the RuAl—X layer selected from C and oxides of Si, Ti, W, Zr, and Hf, to facilitate heat transfer away from the FePt recording layer
Implementation Method 2
The most common type of proposed HAMR disk drive uses a laser source and an optical waveguide with a near-field transducer (NFT)
Implementation Method 3
The NFT is typically located at the air-bearing surface (ABS) of the air-bearing slider that also supports the read/write head and rides or 'flies' above the disk surface
Data Source
AI summary
A heat-assisted magnetic recording (HAMR) medium has a multilayered or laminated heat-sink structure. The laminated heat-sink structure includes a first heat-sink layer and a RuAl—X thermal barrier layer between the medium substrate and the first heat-sink layer. The laminated heat-sink structure may include a second heat-sink layer may between the substrate and the RuAl—X thermal barrier layer. In the RuAl—X thermal barrier layer, X is selected from C and one or more oxides of Si, Ti, W, Zr and Hf. The HAMR medium with the laminated heat-sink structure reduces the amount of required laser current as compared to a similar HAMR medium with a conventional single heat-sink layer of the same thickness, while also slightly improving magnetic properties and recording performance.