Multilayer Plasmon Generator Hardness and Thermal Stability
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Solution Overview
Problem
Plasmon generators formed entirely of Au or Ag in thermally-assisted magnetic recording heads face issues with reliability due to softness, thermal expansion, and degradation, leading to reduced heating performance and potential damage to the recording medium.
Innovation Solution
A plasmon generator with a multilayer structure, comprising a first metal layer, a second metal layer, and an intermediate layer of higher Vickers hardness, where the intermediate layer is interposed between the first and second metal layers, allowing efficient propagation of surface plasmons to the front end face and enhancing mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a plasmon generator is formed entirely of Au or Ag, then near-field light generation is effective, but the front end face becomes significantly recessed due to softness and thermal expansion, degrading heating performance
Solution Approach 1:
The plasmon generator uses a composite structure with a Au or Ag layer for plasmon generation and a harder metal layer (such as Pt, Pd, Ir, Rh, Ru, or their alloys) for mechanical support. This composite structure maintains the near-field light generation efficiency of Au/Ag while preventing front end face recession through the higher hardness and lower thermal expansion of the supporting metal layer.
Solution Approach 2:
The plasmon generator is divided into functional segments: a Au or Ag layer specifically for plasmon excitation and near-field light generation, and a separate harder metal layer for structural support and position maintenance. This segmentation allows each layer to optimize its specific function without compromising the other.
2Reliability
If a plasmon generator is formed entirely of Au or Ag, then plasmon excitation is efficient, but reliability decreases due to softness and deformation
Solution Approach 1:
By combining Au or Ag with harder metals, the invention creates a composite structure that maintains the excellent plasmon properties of Au/Ag while gaining the structural stability and reliability of harder metals. The composite structure prevents deformation and maintains dimensional stability during operation.
Solution Approach 2:
Different regions of the plasmon generator have different material properties optimized for their specific functions: the Au/Ag layer provides excellent plasmon properties where needed, while the harder metal layer provides structural stability in regions requiring mechanical strength. This local quality optimization resolves the contradiction between reliability and manufacturability.
3Power
If the front end face is recessed due to material softness, then heating performance degrades, but using harder materials reduces plasmon generation efficiency
Solution Approach 1:
The composite structure of Au/Ag layer combined with harder metal layers simultaneously achieves both high heating performance (through efficient plasmon generation in Au/Ag) and high material durability (through the hardness and dimensional stability of the supporting metal layers), resolving the contradiction between these two requirements.
Solution Approach 2:
The harder metal layer acts as an intermediary that supports the Au/Ag layer, preventing it from deforming and recessing while allowing the Au/Ag layer to maintain its plasmon generation properties. This intermediary structure enables both high heating performance and material durability.
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 multilayer plasmon generator design improves reliability and maintains heating performance by preventing deformation and damage, ensuring efficient surface plasmon propagation and effective data writing in thermally-assisted magnetic recording.
Implementation Method 1
Surface plasmons are excited on the plasmon generator and propagate along the surface of the plasmon generator to reach the front end face. As a result, the surface plasmons concentrate at the front end face, and near-field light is generated from the front end face based on the surface plasmons.
Implementation Method 2
The front end face generates near-field light based on the surface plasmon.
Data Source
AI summary
A plasmon generator has a front end face, a first metal layer, a second meta-field light based on a surface plasmon. The intermediate layer is interposed between the first metal layer and the second metal layer. Each of the first metal layer, the second metal layer and the intermediate layer has an end located in the front end face. Each of the first and second metal layers is formed of a metal material. The intermediate layer is formed of a material higher in Vickers hardness than the metal material used to form the first metal layer and the metal material used to form the second metal layer.