Thermally-Assisted Recording Head Plasmon Generator Deformation
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Solution Overview
Problem
Thermally-assisted magnetic recording heads face challenges with deformation of the plasmon generator due to heat, leading to reduced recording density and product lifetime, particularly in areas near the air-bearing surface where heat is concentrated.
Innovation Solution
A thermally-assisted magnetic recording head design featuring a metallic layer buried in the gap layer between the magnetic pole and the plasmon generator, where the metallic layer is made of a material with a higher extinction coefficient than the plasmon generator, allowing for resonance and preferential deformation to prevent the plasmon generator from receding from the air-bearing surface, enhancing heat dissipation and maintaining recording density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat is applied to the magnetic disk for thermally-assisted magnetic recording, then the coercivity of the magnetic disk is lowered to enable information writing, but the plasmon generator deforms due to overheating
Solution Approach 1:
A gap layer made of dielectric material is introduced between the magnetic pole and the plasmon generator. This gap layer acts as a thermal insulator and mechanical buffer, preventing direct heat transfer from the magnetic pole to the plasmon generator while maintaining the necessary magnetic field coupling for thermally-assisted magnetic recording.
Solution Approach 2:
A metallic layer with high extinction coefficient is placed in the gap layer to preferentially absorb heat and deform instead of the plasmon generator. The metallic layer serves as a sacrificial element that protects the critical plasmon generator from thermal deformation by taking the heat burden itself.
2Use of energy by moving object
If the plasmon generator is directly irradiated with light for near-field light generation, then the heating efficiency is improved, but the plasmon generator overheats and deforms
Solution Approach 1:
The gap layer serves as a thermal isolation barrier between the magnetic pole (which receives light energy) and the plasmon generator. This allows efficient energy transfer for heating the magnetic disk while preventing excessive temperature accumulation in the plasmon generator.
Solution Approach 2:
The metallic layer in the gap layer acts as a heat sink that preferentially absorbs excess thermal energy through its high extinction coefficient. This sacrificial layer protects the plasmon generator from overheating by dissipating the excess heat away from the critical components.
3Stability of the object's composition
If the plasmon generator deforms due to heat, then the tip section recedes from the air-bearing surface, but recording density is degraded
Solution Approach 1:
The gap layer provides a mechanical buffer that prevents thermal deformation of the plasmon generator from directly affecting its tip position relative to the air-bearing surface. This maintains the precise positioning needed for high recording density while allowing thermal management.
Solution Approach 2:
The metallic layer absorbs thermal stress and deformation preferentially, protecting the plasmon generator's tip position from receding. This ensures the plasmon generator maintains its correct position over the air-bearing surface for maintaining recording density.
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 design effectively suppresses deformation of the plasmon generator, enabling higher-density magnetic recording and increased product lifetime by efficiently dissipating heat and maintaining the plasmon generator's position over the air-bearing surface.
Implementation Method 1
the metallic layer is made of a material with a higher extinction coefficient than the plasmon generator, allowing for resonance and preferential deformation
Implementation Method 2
near-field light is applied to a magnetic recording medium to lower a coercivity thereof so as to record information
Implementation Method 3
allowing frequency of light to coincide with a resonant frequency of plasmons that are generated in a metal, by directly applying the light to a plasmon generator
Data Source
AI summary
The thermally-assisted magnetic recording head includes: a magnetic pole having an end exposed on an air-bearing surface; a waveguide; a plasmon generator provided between the magnetic pole and the waveguide, and having a first region and a second region, the first region extending backward from the air-bearing surface to a first position, and the second region being coupled with the first region at the first position and extending backward from the first position; a gap layer provided between the magnetic pole and the first region of the plasmon generator and extending backward from the air-bearing surface to the first position, and being formed of a dielectric material; and a metallic layer buried in the gap layer, and extending forward from a second position that is located between the air-bearing surface and the first position.