Near-field light generator plasmon generator MgO layer thermal stress
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Solution Overview
Problem
Thermally-assisted magnetic recording heads face challenges in preventing plasmon generator deformation due to temperature rises, which can impair heating capability and reliability, while maintaining waveguide efficiency.
Innovation Solution
Incorporating an MgO layer in contact with the plasmon generator's outer surface, excluding the near-field light generating part, and ensuring the cladding has a lower refractive index than the core and MgO layer, to prevent deformation and heat dissipation issues without degrading waveguide efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the plasmon generator is disposed close to the medium facing surface to enable thermally-assisted magnetic recording, then heating capability is improved, but the plasmon generator rises in temperature causing deformation and reliability issues
Solution Approach 1:
An MgO layer is introduced as an intermediary between the plasmon generator and the magnetic recording medium. This layer serves multiple functions: it enhances adhesion to prevent deformation, provides thermal management to reduce temperature rise, and maintains the necessary proximity for effective heating while protecting the plasmon generator from direct contact stresses.
Solution Approach 2:
The system uses a composite structure combining the plasmon generator material (such as gold or silver) with the MgO layer. This composite configuration leverages the high thermal conductivity and adhesion properties of MgO while maintaining the plasmonic properties of the metal layer, achieving both heating capability and reliability.
2Temperature
If the plasmon generator rises in temperature to provide heating, then thermally-assisted magnetic recording is enabled, but the plasmon generator deforms due to atomic migration and loses heating capability
Solution Approach 1:
The MgO layer is positioned beforehand to cushion and support the plasmon generator during thermal cycles. This protective layer prevents direct thermal stress and atomic migration that would cause deformation, allowing the plasmon generator to maintain its shape while still achieving the necessary temperature rise for heating.
Solution Approach 2:
The introduction of the MgO layer changes the thermal and mechanical parameters of the plasmon generator system. It modifies the thermal conductivity distribution and mechanical stress distribution, allowing the plasmon generator to operate at elevated temperatures without deforming due to the altered parameter landscape.
3Use of energy by moving object
If a material with low dielectric loss is used for the plasmon generator to reduce heat generation, then heating efficiency is improved, but the material may be softer and more susceptible to deformation at elevated temperatures
Solution Approach 1:
The system employs a composite material approach where the plasmon generator uses a material with low dielectric loss (such as gold or silver) for high heating efficiency, while the MgO layer provides the necessary mechanical strength and thermal management. This composite structure allows each material to contribute its optimal properties without compromising the other.
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 MgO layer enhances adhesion, reduces thermal stress, and improves heat dissipation, preventing plasmon generator deformation and maintaining waveguide efficiency, thus ensuring reliable thermally-assisted magnetic recording.
Implementation Method 1
The waveguide includes a core through which light propagates
Implementation Method 2
a surface plasmon is excited on the plasmon exciting part based on the light propagating through the core
Implementation Method 3
Part of the energy of the light guided to the plasmon generator through the waveguide is transformed into heat in the plasmon generator
Implementation Method 4
The MgO layer is in contact with at least part of the outer surface of the plasmon generator excluding the near-field light generating part
Data Source
AI summary
A near-field light generator includes a waveguide, a plasmon generator, and an MgO layer. The waveguide includes a core and a cladding. The plasmon generator has an outer surface including a plasmon exciting part and a near-field light generating part, and is configured so that a surface plasmon is excited on the plasmon exciting part based on light propagating through the core, and the near-field light generating part generates near-field light based on the surface plasmon. The MgO layer is in contact with at least part of the outer surface of the plasmon generator excluding the near-field light generating part, and not in contact with the core. The cladding is lower in refractive index than the core and the MgO layer.