Thermally-Assisted Magnetic Recording Head Cladding Design
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Solution Overview
Problem
In thermally-assisted magnetic recording systems, the plasmon generator is prone to agglomeration due to thermal expansion near the air-bearing surface, leading to reduced near-field light generation and deteriorated recording performance.
Innovation Solution
A thermally-assisted magnetic recording head with a cladding layer having a first section with a higher thermal expansion coefficient near the air-bearing surface and a second section farther away, which reduces stress on the plasmon generator and prevents agglomeration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the plasmon generator is located near the air-bearing surface to generate near-field light, then recording performance is improved, but thermal expansion causes agglomeration of the plasmon generator
Solution Approach 1:
The cladding layer is divided into two sections with different thermal expansion coefficients: a first section near the air-bearing surface with a larger thermal expansion coefficient and a second section farther away with a smaller thermal expansion coefficient. This local differentiation allows the structure to better accommodate thermal expansion near the heat source while maintaining overall stability, preventing agglomeration of the plasmon generator and ensuring reliable near-field light generation for recording.
2Power
If the forward section of the plasmon generator is exposed to high temperature and high pressure environment, then near-field light generation is enhanced, but the forward section is more easily agglomerated
Solution Approach 1:
The invention changes the thermal expansion coefficient parameter of the cladding layer material in different spatial regions. By selecting materials with appropriate thermal expansion coefficients for the first and second sections, the structure can withstand thermal and mechanical stresses without agglomeration, maintaining the plasmon generator's position and reliability while still enabling near-field light generation in the high-temperature zone.
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 stabilizes the recording operation by minimizing agglomeration of the plasmon generator, ensuring superior recording performance by maintaining the plasmon generator's proximity to the air-bearing surface.
Implementation Method 1
a waveguide 32 allowing the laser light to propagate therethrough
Implementation Method 2
surface plasmon polariton coupling is used to prevent overheating of a plasmon generator due to direct application of light. In this case, the light propagating through a waveguide (guided light) is not directly applied to the plasmon generator, and the guided light is coupled with the plasmon generator through evanescent coupling, and thus surface plasmon polaritons are generated on a surface of the plasmon generator.
Implementation Method 3
when surface plasmons are generated by the plasmon generator, near-field light is generated in the vicinity of the air-bearing surface by using the surface plasmons, and therefore heat is supplied together with the recording magnetic field to the magnetic disk.
Implementation Method 4
the guided light is coupled with the plasmon generator through evanescent coupling
Implementation Method 5
a magnetic pole generating a recording magnetic field
Implementation Method 6
coercivity of the recording region is lowered with increase in temperature as well as the recording region is magnetized, and thus information is recorded
Data Source
AI summary
The thermally-assisted magnetic recording head of the invention includes: a waveguide; a magnetic pole; a cladding layer provided between the waveguide and the magnetic pole; and a plasmon generator embedded in the cladding layer. The cladding layer includes a first cladding section located on a side close to an air-bearing surface and a second cladding section located on a side far from the air-bearing surface, and a thermal expansion coefficient of the first cladding section is larger than a thermal expansion coefficient of the second cladding section.