TAMR Head Plasmon Generator Deformation Control
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Solution Overview
Problem
The existing thermal assisted magnetic recording heads face challenges in maintaining the deformation of the plasmon generator while improving recording performance, as factors other than heat generation accelerating deformation have not been adequately addressed, leading to reliability issues and reduced recording density.
Innovation Solution
The thermal assisted magnetic recording head incorporates a metal protective layer and an overcoat protective layer formed on a flat surface to alleviate mechanical stress, preventing the occurrence of heterophase parts and thus suppressing deformation of the plasmon generator, while maintaining the configuration for improved recording performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the plasmon generator is made with gold (Au) to generate near-field light efficiently, then the efficiency of surface plasmon propagation is improved, but the plasmon generator is prone to agglomeration and deformation due to heat and stress
Solution Approach 1:
The patent applies composite materials by combining gold (Au) with a small amount of copper (Cu) or iron (Fe) to create an alloy plasmon generator. This composite structure maintains the excellent surface plasmon propagation efficiency of gold while incorporating the enhanced mechanical strength and heat resistance of copper or iron, thereby suppressing agglomeration and deformation under thermal and stress conditions.
Solution Approach 2:
The patent modifies the compositional parameters of the plasmon generator by adding specific amounts (0.2 at % to 2.0 at %) of copper or iron to gold. This parameter change optimizes the balance between maintaining plasmon propagation efficiency and improving structural stability, preventing the harmful agglomeration phenomenon while preserving the desired optical properties.
2Reliability
If copper (Cu) or iron (Fe) is added to Au to suppress agglomeration, then the hardness and reliability of the plasmon generator are improved, but plasmon propagation loss increases and heat generation occurs
Solution Approach 1:
The patent precisely controls the concentration parameters of copper or iron additives within the range of 0.2 at % to 2.0 at %. This optimized parameter selection ensures sufficient improvement in hardness and agglomeration resistance while minimizing the increase in plasmon propagation loss and associated heat generation, achieving an optimal balance between reliability and energy efficiency.
3Productivity
If the magnetic grains are reduced in size to enhance recording density, then the recording density is improved, but the thermal stability of magnetization is reduced
Solution Approach 1:
The patent changes the physical parameter of magnetic grain size to increase recording density, while simultaneously applying thermal assistance through the plasmon generator to temporarily reduce coercive force during recording. This allows smaller magnetic grains to be used without permanently compromising thermal stability, as the heat from the plasmon generator enables writing to high-coercivity media during operation.
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 configuration effectively suppresses the deformation of the plasmon generator, ensuring reliable and long-term excellent thermal assisted magnetic recording by reducing mechanical stress and maintaining recording performance.
Implementation Method 1
The plasmon generator is coupled with portion of the propagated light propagates in the core in the surface plasmon mode and generates a surface plasmon, propagates the surface plasmon up to the end surface situated on the air bearing surface, and generates near-field light at the end surface
Implementation Method 2
the metal protective layer configures a part of the flat surface... the overcoat protective layer has a flat bottom surface at least at a position where it overlaps with the main pole... effectively suppresses the deformation of the plasmon generator, ensuring reliable and long-term excellent thermal assisted magnetic recording by reducing mechanical stress
Implementation Method 3
A magnetic recording medium is a discontinuous medium in which magnetic grains are aggregated... a core that propagates light irradiated from a laser diode
Implementation Method 4
When information is recorded, a magnetic field and heat are simultaneously applied to a portion of the magnetic recording medium where information is recorded, and temperature of the portion is increased. Information is recorded to the portion where the magnetic coercive force has been decreased with this process by the magnetic field.
Data Source
AI summary
A thermal assisted magnetic recording head executing magnetic recording while locally heating a magnetic recording medium includes a plasmon generator generating surface plasmon and generating near-field light from the surface plasmon at an end surface situated on an air bearing surface facing the magnetic recording medium, a main pole being in contact with the plasmon generator and exposed on the air bearing surface, a metal protective layer situated on an opposite side to the plasmon generator when viewed from the main pole and positioned to overlap with a part of the main pole when viewed from one side in a down track direction, and an overcoat protective layer covering the metal protective layer. The overcoat protective layer is formed on a flat surface at least at a position where it overlaps with the main pole when viewed from one side in the down track direction, and the metal protective layer configures a part of the flat surface. Moreover, the overcoat protective layer has a flat bottom surface at least at a position where it overlaps with the main pole when viewed from one side in the down track direction.