Magnetic Stack Heat-Sink Layout for HAMR Thermal Gradient Stability
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Solution Overview
Problem
In heat-assisted magnetic recording (HAMR) technology, managing thermal gradients and power applied to the laser for efficient data storage is challenging, leading to a trade-off between areal density capability and cumulative failure rate due to heat flowback and thermal stress.
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 to create thermal resistance, thereby optimizing thermal gradient and areal density capacity.
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 and manufacturing is easier, but the thermal gradient control is insufficient and laser power requirements are higher
Solution Approach 1:
The heat-sink layer is segmented into multiple distinct layers (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 of the heat-sink structure to perform different thermal management functions, optimizing the thermal gradient for HAMR operations.
Solution Approach 2:
Different portions of the heat-sink structure are assigned different thermal conductivities to optimize local thermal performance. The second heat-sink layer (with lower thermal conductivity ≤50 W/(m*K)) is positioned closer to the magnetic recording structure to maintain thermal gradient, while the first heat-sink layer (with higher thermal conductivity) is positioned farther away to dissipate heat efficiently. This local differentiation of thermal properties resolves the contradiction between thermal gradient control and structural simplicity.
2Temperature
If higher laser power is applied to heat the magnetic recording disk, then the thermal gradient improves for better recording performance, but the cumulative failure rate increases due to thermal stress
Solution Approach 1:
The second heat-sink layer acts as a thermal intermediary between the magnetic recording structure and the first heat-sink layer. With thermal conductivity of 50 W/(m*K) or less, it provides thermal resistance that prevents excessive heat flowback to the magnetic recording structure, thereby reducing thermal stress and cumulative failure rate while maintaining the thermal gradient necessary for recording performance.
3Loss of energy
If the thermal conductivity of the heat-sink layer is increased to dissipate heat faster, then thermal stress is reduced, but the thermal gradient required for HAMR is compromised
Solution Approach 1:
The heat-sink structure is divided into two layers with different thermal conductivities. The second heat-sink layer (closer to magnetic recording structure) has lower thermal conductivity (≤50 W/(m*K)) to maintain thermal gradient, while the first heat-sink layer (farther from magnetic recording structure) has higher thermal conductivity for efficient heat dissipation. This segmentation resolves the contradiction between heat dissipation and thermal gradient maintenance.
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, minimizing thermal stress and 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
Implementation Method 2
Managing the thermal gradient in the magnetic recording disk and the power applied to the laser
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.