Tapered Bi-Layer Near-Field Transducer for HAMR Heat Reliability
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Solution Overview
Problem
Existing heat-assisted magnetic recording (HAMR) write heads face reliability issues due to high operation temperatures near the Curie temperature of FePt, which can lead to material recession and reduced performance.
Innovation Solution
A bi-layer near-field transducer (NFT) structure with a bottom taper is introduced, comprising a gold plasmon generator layer and a thermo-mechanically stable layer like Rhodium or Iridium, forming an angle of 30-60 degrees relative to the air-bearing surface, enhancing heat transfer and material stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer near-field transducer is used, then the structure is simpler, but the temperature control and material stability are insufficient at high operation temperatures near the Curie temperature of FePt
Solution Approach 1:
The patent employs a bi-layer structure where the first layer is a plasmon generator material (e.g., gold) and the second layer is a thermo-mechanically stable material (e.g., rhodium, iridium, or platinum). This composite structure combines the optical properties needed for plasmon generation with the thermal stability required to withstand high operation temperatures near the Curie temperature of FePt, thereby improving material stability without excessive complexity
Solution Approach 2:
The near-field transducer is divided into two distinct functional layers: the first layer dedicated to plasmon generation and the second layer dedicated to thermal stability. This segmentation allows each layer to be optimized for its specific function, with the first layer handling optical-to-thermal energy conversion and the second layer providing thermal management and structural stability at high temperatures
2Productivity
If the near-field transducer operates at high temperatures to enhance write performance, then write performance improves, but material recession increases and reliability decreases
Solution Approach 1:
The second layer of thermo-mechanically stable material acts as an intermediary between the plasmon generator and the magnetic recording medium. It mediates the thermal effects by providing a stable interface that resists material recession while allowing sufficient heat transfer to the medium for enhanced write performance, thus protecting against reliability issues at high temperatures
Solution Approach 2:
The patent changes the material parameters of the near-field transducer by introducing a bi-layer composition with specific material properties. The first layer has high plasmonic properties for efficient energy conversion, while the second layer has high thermal stability parameters that prevent material recession at operation temperatures near the Curie point, enabling reliable high-performance writing
3Reliability
If a tapered bi-layer structure is used, then heat transfer efficiency improves and material stability increases, but manufacturing complexity increases
Solution Approach 1:
The tapered structure introduces local quality variations in the thickness of the bi-layer transducer, with the taper angle varying along the length of the transducer. This local variation optimizes heat transfer efficiency at different positions while maintaining material stability, allowing enhanced thermal coupling with the magnetic medium without compromising the structural integrity or increasing overall manufacturing complexity excessively
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 bi-layer structure improves reliability and performance by reducing plasmon generator temperature and minimizing material recession, maintaining efficiency without trade-offs.
Implementation Method 1
a plasmon generator (PG) layer, and a second layer... The PG layer and the second layer can form a taper angle relative to the ABS ranging between 30 and 60 degrees
Implementation Method 2
The second layer can include a thermo-mechanically stable material disposed adjacent to the PG layer... which can enhance write performance of the write head to the magnetic recording medium
Data Source
AI summary
The present embodiments relate to a heat-assisted magnetic recording (HAMR) write head with a NFT bi-layer structure with a bottom taper, which can be applied to one or both layers of the two layers. A heat-assisted magnetic recording (HAMR) write head can include a main pole including a tip portion configured to interact with a magnetic recording medium at an air-bearing surface (ABS). The HAMR write head can further include a near-field transducer (NFT) that includes a dielectric waveguide, a plasmon generator (PG) layer, and a second layer. The second layer can include a thermo-mechanically stable material disposed adjacent to the PG layer. Further, the PG layer and the second layer can form a taper angle relative to the ABS ranging between 30 and 60 degrees.