Thermally-Assisted Magnetic Recording Head Plasmon Generator Agglomeration
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Solution Overview
Problem
Thermally-assisted magnetic recording heads face challenges with agglomeration of plasmon generators due to temperature increases, leading to decreased recording performance and product lifetime, especially when using gold as the plasmon generator material.
Innovation Solution
A thermally-assisted magnetic recording head design featuring a waveguide, magnetic pole, and plasmon generator with distinct protective films, where the first film is diamond-like carbon and the second film is tantalum oxide, covering the plasmon generator to prevent agglomeration and enhance heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light is directly applied to a plasmon generator to generate near-field light, then near-field light generation is achieved, but the plasmon generator overheats and deforms
Solution Approach 1:
A waveguide is introduced as an intermediary component between the light source and the plasmon generator. The waveguide transmits light to the plasmon generator indirectly, preventing direct application of light to the plasmon generator and thereby avoiding overheating and deformation while still enabling near-field light generation.
2Productivity
If magnetic microparticles are made small in size to increase recording density, then recording density is improved, but thermal stability of magnetization is lowered
Solution Approach 1:
The invention changes the parameter of anisotropy energy of the magnetic microparticles by using materials with higher anisotropy energy, such as perpendicular magnetic layers. This allows the magnetic microparticles to maintain thermal stability even when made small in size, thereby enabling higher recording density without sacrificing thermal stability.
3Stability of the object's composition
If anisotropy energy of magnetic microparticle is increased to improve thermal stability, then thermal stability is improved, but coercivity increases making information recording difficult
Solution Approach 1:
The invention applies periodic heating using near-field light generated by the plasmon generator. The heating is applied periodically or pulsedly to the magnetic recording medium, temporarily reducing the coercivity of the magnetic microparticles to enable information recording, while maintaining high anisotropy energy for thermal stability during non-heating periods.
Solution Approach 2:
The invention dynamically changes the temperature parameter of the magnetic recording medium during the recording process. By applying heat through near-field light, the coercivity is temporarily reduced, enabling information recording. After heating, the magnetic microparticles return to their high anisotropy energy state, maintaining thermal stability.
4Illumination intensity
If gold is used as plasmon generator material to generate near-field light, then near-field light generation is improved, but agglomeration occurs due to temperature increase
Solution Approach 1:
The waveguide acts as an intermediary that transmits light to the gold plasmon generator without allowing direct absorption of light energy by the gold. This indirect light transmission prevents excessive heating of the gold, thereby preventing agglomeration while maintaining effective near-field light generation.
Solution Approach 2:
The invention creates a thermal environment that prevents agglomeration of the gold plasmon generator. By using the waveguide to control light incidence, the gold is protected from excessive temperature increases that would cause agglomeration, effectively creating a stable thermal environment for the gold material.
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 agglomeration and allows for higher-density magnetic recording while extending the product's lifetime by using materials with appropriate mechanical and thermal properties for each film layer.
Implementation Method 1
light propagating through a waveguide (guided light) is not directly applied to a plasmon generator, but the guided light is coupled to the plasmon generator through evanescent coupling
Implementation Method 2
surface plasmon polaritons generated on a surface of the plasmon generator are utilized
Implementation Method 3
frequency of light to coincide with a resonant frequency of plasmons that are generated in a metal
Implementation Method 4
heat is applied together with the magnetic field to a section of the magnetic recording medium where the information is to be written to increase the temperature and lower the coercivity
Implementation Method 5
a magnetic field to a section of the magnetic recording medium where the information is to be written to increase the temperature and lower the coercivity
Data Source
AI summary
This thermally-assisted magnetic recording head includes: a waveguide having a first end surface included in an air bearing surface; a magnetic pole having a second end surface included in the air bearing surface; a plasmon generator having a third end surface included in the air bearing surface; a first film covering the first end surface of the waveguide and the second end surface of the magnetic pole, and having an opening in a region corresponding to the third end surface of the plasmon generator; and a second film filling the opening and covering the third end surface of the plasmon generator.