Thermally-Assisted Magnetic Recording Head Heat Radiation Layer
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Solution Overview
Problem
Thermally-assisted magnetic recording heads face performance and reliability deterioration due to temperature increases during the recording process, leading to thermal deformations and reduced magnetization stability in both the recording medium and the head itself.
Innovation Solution
A thermally-assisted magnetic recording head is designed with a waveguide having a core and a cladding with a heat radiation layer made of high thermal conductivity materials, such as Au, Ag, or Cu, embedded in the cladding at the air bearing surface to dissipate heat effectively, thereby suppressing temperature increases and maintaining performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermally-assisted magnetic recording is performed using laser light to heat the magnetic recording medium, then the coercive force of the magnetic recording medium is decreased enabling information recording, but the temperature of the magnetic recording head itself increases causing performance deterioration and reliability reduction
Solution Approach 1:
The patent extracts the heat radiation function from the waveguide structure by embedding a separate heat radiation layer made of high thermal conductivity material (Au, Ag, or Cu) into the cladding. This layer is specifically positioned at the air bearing surface to extract heat from the head, thereby reducing the head temperature while maintaining the recording function.
Solution Approach 2:
The heat radiation layer is locally positioned at the air bearing surface where heat dissipation is most critical. The layer has different thermal conductivity properties than the surrounding cladding material, creating a localized heat extraction zone that targets the specific area experiencing thermal issues during recording operations.
2Productivity
If the size of magnetic microparticles is decreased to increase recording density, then the recording density is improved, but the thermal stability of magnetization of the magnetic microparticles is decreased
Solution Approach 1:
The patent changes the thermal parameter (temperature) of the magnetic recording medium during recording by applying laser heating. This temporary parameter change reduces the coercive force at the moment of recording, enabling successful writing to smaller magnetic microparticles that would otherwise be too stable to modify. The heating is localized and temporary, affecting only the recording zone during the writing process.
3Stability of the object's composition
If the anisotropy energy of magnetic microparticles is increased to improve magnetization stability, then the magnetization stability is improved, but the coercive force of the magnetic recording medium is increased making recording difficult
Solution Approach 1:
The patent temporarily changes the temperature parameter of the magnetic recording medium during the recording process. By heating the medium with laser light, the coercive force is reduced at the moment of recording, enabling successful writing to particles with high anisotropy energy. After the recording pulse, the temperature returns to normal and the high coercive force restores magnetization stability.
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 solution effectively reduces thermal deformations and maintains high performance and reliability by efficiently dissipating heat away from the air bearing surface, ensuring stable magnetization and prolonged head functionality.
Implementation Method 1
a heat radiation layer which is embedded in the cladding surrounding the periphery of the core on the air bearing surface and is made of a material having a higher thermal conductivity coefficient than the cladding
Implementation Method 2
a laser light source is used to heat the magnetic recording medium... one method is to heat the magnetic recording medium by guiding laser light to a recording unit via a waveguide
Implementation Method 3
the other method is to heat the magnetic recording medium by converting the laser light to near-field light (a near-field light heating type). The near-field light is a type of electromagnetic field that is formed around a substance
Data Source
AI summary
A thermally-assisted magnetic recording head that includes an air bearing surface facing a recording medium and that performs a magnetic recording while heating the recording medium includes a waveguide configured with a core through which light propagates and a cladding that surrounds a periphery of the core and that includes at least a portion extending to the air bearing surface; and a heat radiation layer that is embedded in the cladding that surrounds the periphery of the core on the air bearing surface, and that is made of a material having a higher thermal conductivity coefficient than the cladding.