HAMR Head NFT Trailing Bevel for Optical Spot Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in magnetic recording is to achieve higher storage densities while maintaining thermal stability of data, as grain size limitations and superparamagnetic effects hinder further reduction, and existing HAMR systems face complex manufacturing processes and dimension control issues.
Innovation Solution
The introduction of HAMR heads with trailing beveled near-field transducers (NFTs) and simplified manufacturing processes, which include a dielectric layer and pole diffusion barrier, allow for better control over the distance between the waveguide and NFT, simplifying the manufacturing and enhancing performance by concentrating light and adjusting the optical near-field spot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If grain size is reduced to increase storage density, then storage capacity improves, but thermal stability deteriorates due to superparamagnetic effects
Solution Approach 1:
The patent changes the temperature parameter dynamically during the writing process. By heating the magnetic media to elevated temperatures (approaching the Curie temperature), the coercivity and magneto-crystalline anisotropy are reduced, enabling data writing in high-anisotropy materials. After writing, the media cools to ambient temperature where the same materials provide thermal stability. This temporal parameter change resolves the contradiction between achieving high storage density with small grains and maintaining thermal stability.
2Ease of manufacture
If conventional optical coupling is used between waveguide and NFT, then manufacturing is simpler, but control over waveguide-NFT distance is poor
Solution Approach 1:
The patent introduces a dielectric layer as an intermediary between the waveguide and the NFT. This dielectric layer serves as a spacer that mechanically defines and controls the separation distance between the waveguide and NFT with high precision. The intermediary structure enables accurate distance control while maintaining manufacturing feasibility through standard deposition and etching processes.
3Manufacturing precision
If complex manufacturing processes are used to achieve precise dimensions, then HAMR head performance improves, but manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary structuring of the NFT by forming a trailing bevel during the deposition process itself, before final assembly. This preliminary action establishes precise geometric features and spacing relationships early in the manufacturing sequence, enabling subsequent steps to proceed with standard processes while maintaining high dimensional accuracy. The trailing bevel is created as part of the NFT formation, preventing the need for complex post-processing alignment operations.
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 improves the thermal stability of data storage and simplifies the manufacturing process, enabling more precise control over the dimensions and performance of HAMR heads, thus overcoming the limitations of grain size and superparamagnetic effects.
Implementation Method 1
A strong optical near-field is generated at the apex of the NFT output end. The NFT couples light onto the media at a spot of a size that is smaller than the optical diffraction limit, which heats a region of the media.
Implementation Method 2
An evanescent wave generated at a surface of the waveguide couples to surface plasmons excited on the surface of the NFT, and a strong optical near-field is generated at the apex of the NFT output end.
Implementation Method 3
the magnetic recording material is heated to near or above its Curie temperature. As a result, the temperature of the area increases and the coercivity decreases, thereby enabling the data to be written at a relatively modest field.
Data Source
AI summary
Disclosed herein are embodiments of a heat-assisted magnetic recording (HAMR) head that includes a near-field transducer (NFT) with a trailing bevel. Also disclosed are sliders and data storage devices comprising those HAMR heads, and methods of manufacturing HAMR heads with NFTs having trailing bevels. A HAMR head comprises a waveguide core, a main pole, and a NFT comprising a trailing beveled edge at an acute angle to an air-bearing surface (ABS) of the HAMR head. A method of fabricating a HAMR head comprises depositing material for a NFT, creating a trailing-side surface of the NFT, and creating a trailing beveled edge in the trailing-side surface of the NFT at the ABS, and forming a dielectric layer over the trailing beveled edge. The trailing beveled edge is at an acute angle to the ABS, and a remainder of the trailing-side surface of the NFT is substantially perpendicular to the ABS.