TAMR Write Head Optical Side Shields for Thermal Gradient Control
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Solution Overview
Problem
The reliability and performance of Thermally Assisted Magnetic Recording (TAMR) write heads are compromised due to excessive heat from optical radiation, which degrades the thermal stability of the head and blurs the recording spot on the magnetic medium, limiting recording density and quality.
Innovation Solution
An optically shielded TAMR write head design incorporating a waveguide blocker and optically opaque side shields to suppress loosely coupled optical radiation, enhancing thermal gradients and reducing head temperature, thereby sharpening the heated region and improving recording quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optical radiation is used for thermal activation in TAMR, then magnetic recording density can be enhanced, but excessive heat degrades head thermal stability and blurs recording spots
Solution Approach 1:
The optical radiation path is segmented by introducing waveguide blockers and optical side shields that divide and redirect the optical path, preventing excessive heat from reaching the head while maintaining thermal activation at the recording spot
Solution Approach 2:
Optical side shields act as intermediary elements between the optical radiation source and the head, absorbing or redirecting excessive optical energy before it reaches the head, thereby mediating the thermal interaction
2Manufacturing precision
If optical side shields are added to suppress loose coupling, then thermal gradients are enhanced by 20-30%, but device complexity increases
Solution Approach 1:
Optical side shields are strategically positioned only where needed to block loose-coupled optical radiation, providing localized thermal management without requiring complete restructuring of the head assembly
Solution Approach 2:
The optical side shields are positioned asymmetrically relative to the waveguide and plasmon generator, optimized to block specific angles of loose-coupled radiation while maintaining symmetry in the functional recording region
3Manufacturing precision
If magnetic fine particles are made smaller to increase recording density, then bit boundary irregularities are reduced, but thermal stability of magnetization deteriorates
Solution Approach 1:
The patent changes the thermal parameter (temperature) locally at the recording spot through optical heating, temporarily reducing the coercivity of the magnetic medium to enable writing on smaller particles that would otherwise be too stable to modify
Solution Approach 2:
The optical radiation is applied in a controlled, periodic manner to provide thermal activation only during the writing process, allowing the magnetic particles to be modified when heated and then stabilize when cooled
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 unwanted optical radiation, enhancing down-track and cross-track thermal gradients by 20-30% and improving the peg-width/track-pitch ratio, leading to sharper recording spots and improved system performance without reducing the plasmon generator's thermo-mechanical stability.
Implementation Method 1
The waveguide propagated electromagnetic radiation is transferred, by electromagnetic coupling, to a plasmon generator (PG) adjacent to (above or below) the waveguide at the distal end of the waveguide
Implementation Method 2
The plasmon generator is usually made of highly conductive material such as Au or Ag. The optical radiation coupled by the waveguide to the plasmon generator is in turn coupled to the recording medium via plasmon near-field energy, and, thus, heats the surface of recording media
Implementation Method 3
optically opaque side shields to suppress loosely coupled optical radiation
Data Source
AI summary
An optically shielded TAMR (thermally assisted magnetic recording) write head has a metal waveguide blocker formed against a distal end of a waveguide and a pair of symmetrically disposed optical side shields formed to either side of a plasmon generator formed above the waveguide. The waveguide focuses optical radiation on the adjacent plasmon generator where it excites plasmon modes that heat the recording medium with near-field energy and the waveguide blocker prevents excess optical radiation from blurring the spot on the recording region. The optical side shields further restrict loosely coupled optical radiation from reaching the recording region and blurring the optical spot and improves down-track and cross-track thermal gradients.