C-Shaped Near-Field Transducer With Rh Peg for HAMR
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Solution Overview
Problem
In heat-assisted magnetic recording (HAMR) devices, achieving a high thermal gradient while maintaining mechanical strength is challenging due to the conflicting requirements of using plasmonic metals like Au and Ag, which are mechanically weak but effective for generating surface plasmon polaritons.
Innovation Solution
A C-shaped near-field transducer (NFT) with a nanorod peg made of a robust metal, such as Rh or Ir, is used, where surface plasmon polaritons are resonantly excited and coupled to the peg via a barrier layer, enhancing the thermal gradient and mechanical reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If plasmonic metals like Au and Ag are used to generate surface plasmon polaritons, then the thermal gradient is enhanced, but the mechanical strength decreases
Solution Approach 1:
The patent employs a composite structure where a robust metal (Rh or Ir) serves as the structural backbone providing mechanical strength, while a plasmonic metal layer (Au or Ag) is deposited on its surface to generate surface plasmon polaritons. This composite approach allows simultaneous achievement of high thermal gradient (>10K/nm) and mechanical reliability, resolving the contradiction between thermal performance and structural integrity
Solution Approach 2:
The invention applies different material properties to different parts of the near-field transducer: the bulk structure uses mechanically strong metals (Rh/Ir) while the surface layer uses plasmonic metals (Au/Ag) for optical functionality. This local differentiation of material quality enables each region to optimize for its specific function without compromising the other
2Strength
If a robust metal like Rh or Ir is used for the peg structure, then mechanical strength is improved, but the ability to generate surface plasmon polaritons is reduced
Solution Approach 1:
The patent creates a functional composite where the robust metal (Rh/Ir) provides mechanical support and the thin plasmonic metal layer (Au/Ag) provides optical functionality. The plasmonic layer, though thin, is sufficient to generate surface plasmon polaritons while the underlying robust metal ensures structural integrity, thus resolving the contradiction between mechanical strength and plasmonic functionality
Solution Approach 2:
The near-field transducer is segmented into two functional layers: a structural layer made of robust metal and a functional layer made of plasmonic metal. This segmentation allows each layer to be optimized independently for its specific purpose - mechanical support versus plasmon generation - eliminating the need to choose between the two conflicting requirements
3Temperature
If the near-field transducer is operated at high temperatures, then the thermal gradient for heating the magnetic recording medium is improved, but the integrity of the NFT is compromised due to misshaping or recess formation
Solution Approach 1:
The patent uses a composite structure where the robust metal (Rh/Ir) acts as a thermally stable backbone that resists deformation at high temperatures, while the plasmonic metal layer (Au/Ag) generates the necessary thermal gradient. The robust metal's high melting point and structural stability prevent misshaping and recess formation, ensuring NFT integrity during high-temperature operation
Solution Approach 2:
The robust metal structure serves as a pre-established protective framework that cushions the plasmonic metal layer against thermal deformation. This structural reinforcement is built in beforehand to prevent misshaping and recess formation that would otherwise occur during high-temperature operation, thus protecting the NFT's integrity
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 achieves a high thermal gradient greater than 10K/nm, improving the areal data density and reliability of magnetic recording media by maintaining the integrity of the NFT and preventing misshaping or recess formation.
Implementation Method 1
The planar member comprises a bottom surface and is configured to support surface plasmon polaritons (SPPs) that resonantly excite the NFT
Implementation Method 2
The peg coupler portion is separated from the SPP propagator portion by the barrier layer
Data Source
AI summary
An apparatus includes a near-field transducer (NFT) of a heat-assisted magnetic recording head. The NFT includes a substantially C-shaped portion and a peg portion extending from the substantially C-shaped portion. A planar member is disposed adjacent the NFT. The planar member includes a bottom surface configured to support surface plasmon polaritons (SPPs) that resonantly excite the NFT. A barrier member is installed within the planar member and is arranged to encompass at least a tip portion of the peg.