Magnetic Stack Heat-Sink Layers for HAMR Thermal Gradient Control
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Solution Overview
Problem
In heat-assisted magnetic recording (HAMR) hard-disk drives, managing thermal gradients and power applied to the laser for efficient data storage is challenging due to heat flowback and thermal stress, which affects recording performance and increases cumulative failure rates.
Innovation Solution
Incorporating multiple heat-sink layers and interlayers with varying thermal conductivities in the magnetic stack, where the layer farthest from the magnetic recording structure has the highest thermal conductivity, and additional interlayers with lower conductivity are used to manage thermal gradients and prevent heat flowback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a single heat-sink layer is used in the magnetic stack, then the structure is simple, but thermal gradient management is insufficient and heat flowback occurs
Solution Approach 1:
The heat-sink layer is divided into multiple segments (first heat-sink layer and second heat-sink layer) with different thermal conductivities. The second heat-sink layer has thermal conductivity of 50 W/(m*K) or less, while the first heat-sink layer has higher thermal conductivity. This segmentation allows different regions to perform different thermal management functions, improving overall thermal gradient control.
Solution Approach 2:
Different regions of the heat-sink structure are assigned different thermal conductivity properties. The second heat-sink layer (closer to magnetic recording structure) has lower thermal conductivity to prevent heat flowback, while the first heat-sink layer (farther from magnetic recording structure) has higher thermal conductivity for efficient heat dissipation. This local differentiation optimizes thermal management at each position.
2Reliability
If high laser power is applied to heat the magnetic recording disk, then recording performance improves, but thermal stress increases and cumulative failure rates increase
Solution Approach 1:
The second heat-sink layer acts as an intermediary thermal barrier between the magnetic recording structure and the first heat-sink layer. With thermal conductivity of 50 W/(m*K) or less, it mediates heat flow by preventing excessive heat from reaching the magnetic recording structure, thereby reducing thermal stress while maintaining recording performance.
3Ease of manufacture
If thermal conductivity of heat-sink layers is uniform, then manufacturing is simpler, but heat flowback to magnetic recording structure occurs
Solution Approach 1:
The heat-sink structure employs local quality differentiation where the second heat-sink layer has lower thermal conductivity (50 W/(m*K) or less) compared to the first heat-sink layer. This localized property variation prevents heat flowback to the magnetic recording structure while maintaining manufacturing feasibility through standard deposition techniques.
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 configuration enhances thermal gradient and areal density capacity while reducing laser power requirements, improving recording performance and reducing cumulative failure rates.
Implementation Method 1
The second heat-sink layer has a thermal conductivity that is 50 W/(m*K) or less, and that is less than the thermal conductivity of the first heat-sink layer
Data Source
AI summary
A magnetic stack includes a magnetic recording structure and at least two heat-sink layers where heat-sink layer located furthest from the magnetic recording structure has thermal conductivity equal to or greater than intervening heat-sink layers. One or more interlayers can be included in the magnetic stack. Data storage devices and systems including one or more of the magnetic stacks, and related methods.