Thermally Assisted Magnetic Recording Head Plasmon Generator Dielectric Metal Layer
Solution Overview
Problem
Existing thermally assisted magnetic recording heads face challenges in reducing the heating range of magnetic recording media due to the broad generation area of near-field light, which hinders increased recording density.
Innovation Solution
A thermally assisted magnetic recording head design featuring a waveguide, a main pole, a metal layer, and a dielectric body layer, where surface plasmons are generated along the boundaries between these components, concentrating near-field light and allowing for a narrower heating area by controlling the shape of the dielectric body layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of magnetic grains is reduced to increase recording density, then recording density is improved, but thermal stability of magnetization is reduced
Solution Approach 1:
The patent changes the physical state parameter by applying heat to the magnetic recording medium during recording. This temporary temperature increase allows magnetic grains with high coercive force (needed for stability) to be written with existing magnetic heads, resolving the contradiction between thermal stability and recording density
2Stability of the object's composition
If the anisotropic energy of magnetic grains is increased to improve thermal stability, then thermal stability is improved, but coercive force increases making recording difficult
Solution Approach 1:
The patent uses periodic action by applying both magnetic field and heat simultaneously during the recording process. The heat temporarily reduces coercive force, allowing the magnetic field to write information, then the system returns to its normal state, enabling stable storage without requiring permanently high coercive force
3Productivity
If the generation area of near-field light is reduced to narrow heating range, then recording density is improved, but the shape of nonmagnetic metal layer becomes complicated making manufacturing difficult
Solution Approach 1:
The patent introduces a dielectric layer as an intermediary between the nonmagnetic metal layer and the magnetic recording medium. This dielectric layer acts as a mediator that shapes and confines the near-field light generation area without requiring complex metal layer geometries, simplifying manufacturing while achieving narrow heating range
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 narrows the near-field light generation area, reducing the heating range of the magnetic recording medium and enhancing recording density, while maintaining the long-term reliability of the magnetic head.
Implementation Method 1
a metal layer that is positioned between the main pole and the waveguide, that extends from a second end portion positioned on the ABS in a height direction, that generates a surface plasmon from the propagating light, and that generates near field light (NF light) from the surface plasmons at the second end portion
Implementation Method 2
a dielectric body layer that is surrounded by the metal layer and that extends from a third end portion positioned on the ABS in the height direction
Data Source
AI summary
A thermally assisted magnetic recording head has a waveguide that propagates laser light as propagating light; a main pole that has a first end portion on an air bearing surface (ABS) facing a magnetic recording medium and that emits a magnetic flux to the magnetic recording medium; a metal layer that is positioned between the main pole and the waveguide, that extends from a second end portion positioned on the ABS in a height direction, that generates surface plasmons from the propagating light, and that generates near-field light (NF light) from the surface plasmons at the second end portion; and a dielectric body layer that is surrounded by the metal layer and that extends from a third end portion positioned on the ABS in a height direction.