AuCu Alloy Bi-Layer PPG for HAMR Write Head Thermal Stability
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Solution Overview
Problem
Heat-assisted magnetic recording (HAMR) write heads face challenges in maintaining data storage reliability and lifetime due to the need for smaller magnetic recording medium grain sizes, which can lead to reduced magnetic field strength and thermal stability, causing degradation in recording performance.
Innovation Solution
A bi-layer planar plasmon generator (PPG) structure is implemented in the HAMR write head, featuring an Iridium film as the plasmon generator layer and a gold-copper (AuCu) alloy as the bottom plasmonic layer, with copper comprising between 3-15% of the alloy and a grain size of at least 30 nanometers, to enhance thermal stability and plasmonic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the magnetic recording medium uses smaller grain sizes to increase storage density, then the storage capacity is improved, but the magnetic field strength and thermal stability are reduced
Solution Approach 1:
The patent changes the physical state and properties of materials by implementing a bi-layer PPG structure with specific composition ratios (Ir: 3-15 nm, AuCu: 20-50 nm) and copper content (3-15%). This structural parameter change enables the system to generate sufficient heat to temporarily reduce the thermal stability requirement during writing, while maintaining high storage density with smaller grain sizes.
Solution Approach 2:
The patent uses composite materials in two forms: (1) The AuCu alloy itself is a composite material combining gold and copper with specific ratios to achieve optimal plasmonic properties and thermal stability; (2) The bi-layer PPG structure combines Iridium and AuCu materials with different properties to create a system that generates efficient localized heat while maintaining structural integrity at high temperatures.
2Quantity of substance
If the magnetic recording medium uses smaller grain sizes to increase storage density, then the storage capacity is improved, but the magnetic field strength is reduced
Solution Approach 1:
The patent changes the thermal parameter of the recording medium by introducing localized heating through the PPG structure. This temporary parameter change (heating to near Curie temperature) reduces the magnetic anisotropy energy barrier, enabling smaller grains to be switched with weaker magnetic fields, thus maintaining high storage density without sacrificing writeability.
3Productivity
If the AuCu layer is exposed to high temperatures during HAMR operation, then the recording performance is improved, but the AuCu layer recession increases
Solution Approach 1:
The patent uses the AuCu alloy as a composite material where copper (3-15%) provides enhanced thermal stability and structural support to gold, reducing AuCu layer recession at high temperatures. The bi-layer structure with Iridium (3-15 nm) and AuCu (20-50 nm) creates a composite system where each material compensates for the other's weaknesses under thermal stress.
Solution Approach 2:
The patent applies local quality by creating a bi-layer structure with different material properties at different locations/depths. The Iridium layer provides plasmonic efficiency for heat generation, while the AuCu layer provides thermal stability and structural integrity. This local differentiation allows the system to withstand high temperatures without excessive recession while maintaining recording performance.
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 bi-layer PPG structure improves the robustness of the HAMR write head, maintaining data storage reliability and lifetime by increasing thermal stability and reducing the recession of AuCu layers at high temperatures, thus enhancing recording performance.
Implementation Method 1
In HAMR, optical power from a light source can be converted into localized heating in a recording medium during a write process
Implementation Method 2
HAMR can include heating a small region of the magnetic medium to near its Curie temperature where its coercivity and anisotropy are significantly reduced
Data Source
AI summary
The present embodiments relate to a heat-assisted magnetic recording (HAMR) write head with a bi-layer planar plasmon generator (PPG) structure that includes both an iridium film as a plasmon generator (PG) layer and a gold-copper (AuCu) alloy as a bottom plasmonic layer. A HAMR write head can include a main pole including a tip portion disposed adjacent to an air-bearing surface (ABS). The HAMR write head can also include a heat sink disposed adjacent to the main pole and a bi-layer structure planar plasmon generator (PPG) structure. The PPG structure can also include a plasmon generator (PG) layer comprising an Iridium (Ir) film and a bottom plasmonic layer comprising a gold-copper (Au—Cu) alloy.