HAMR Near-Field Transducer High Refractive Index Layer
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Solution Overview
Problem
Conventional heat assisted magnetic recording (HAMR) heads experience power fluctuations due to reflected light from the near-field transducer (NFT), leading to reduced recording precision and accuracy.
Innovation Solution
A HAMR head with a near-field transducer (NFT) featuring a high refractive index material (HRIM) layer positioned on the leading side taper, which reduces reflectivity and maintains optical efficiency by minimizing light reflection back to the laser diode, thereby stabilizing power fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light is introduced into the NFT in conventional HAMR heads, then the NFT can perform heat assisted magnetic recording, but the NFT reflects some light back to the laser diode causing power fluctuations
Solution Approach 1:
An anti-reflective coating layer is introduced as an intermediary between the NFT and the laser diode. This coating layer acts as a mediator that reduces the reflection of light back to the laser diode, thereby stabilizing laser power while maintaining the NFT's heat assisted magnetic recording capability.
Solution Approach 2:
The refractive index parameters of the anti-reflective coating layer are optimized to minimize light reflection. By changing the optical parameters (refractive index and thickness) of the coating layer, the system achieves reduced reflectivity and stable laser power output during HAMR operations.
2Reliability
If the NFT reflects light back to the laser diode, then power fluctuations occur, but adding anti-reflective coating increases device complexity
Solution Approach 1:
The anti-reflective coating is applied in advance to the NFT surface before the NFT is assembled into the HAMR head. This preliminary action of pre-coating the NFT simplifies the overall manufacturing process and reduces assembly complexity while achieving the desired power stability.
Solution Approach 2:
The anti-reflective coating is formed using composite material structures with specific refractive index profiles. These composite coatings provide effective light reflection reduction while maintaining a compact and manufacturable structure that does not excessively increase device complexity.
3Productivity
If the NFT operates at high temperature for HAMR, then magnetic recording is enabled, but the NFT temperature increases causing potential damage
Solution Approach 1:
The anti-reflective coating, while primarily designed to reduce light reflection, also provides a secondary benefit of thermal management. By reducing the absorbed light energy that would otherwise convert to heat, the coating helps lower the NFT operating temperature, converting the light reflection issue into a thermal management solution.
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 enhances recording precision and accuracy by reducing power fluctuations, increasing optical efficiency, and maintaining mechanical stability, while also decreasing the NFT temperature and improving magnetic field intensity at data transition points.
Implementation Method 1
a high refractive index material (HRIM) layer is positioned on the waveguide core layer 22. The HRIM layer 14 reduces the amount of light reflected by the NFT 12 back to the laser diode 111 by minimizing the refractive index mismatch between the waveguide core layer 22 and the NFT 12
Implementation Method 2
When light from a laser diode is introduced into the NFT in conventional HAMR heads
Implementation Method 3
the NFT 12, which receives semiconductor laser light from a laser diode and transmits it to the NFT 12... heating a portion of the magnetic recording medium prior to a write operation
Implementation Method 4
A waveguide core layer 22 is disposed in the head facing the leading side taper of the NFT 12
Data Source
AI summary
A heat assisted magnetic recording (HAMR) head has a near-field transducer (NFT) with a distal end having a leading side taper inclined at an acute angle to the ABS, such that an acute angle is formed between a leading surface of the leading side taper and the ABS. A main magnetic pole is disposed in the head facing a trailing side of the NFT. A waveguide core layer is disposed in the head facing the leading side taper of the NFT, on which a high refractive index material (HRIM) layer is positioned.