HAMR Write Apparatus Dielectric Gap Thermal Profile Control
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Solution Overview
Problem
Conventional heat-assisted magnetic recording (HAMR) transducers face challenges in controlling the location of the hot spot on magnetic recording media, temperature gradient, and distance between the media hot spot and the write pole, which affects writing performance.
Innovation Solution
Incorporating a dielectric gap between the near-field transducer (NFT) and the main pole, along with a plasmonic ridge and cap, to shift the peak thermal profile closer to the main pole and increase the thermal gradient, thereby improving the heating and magnetic field amplitude on the media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional HAMR transducer uses a waveguide and NFT to focus light to the media, then the media can be heated for magnetic recording, but the location of the hot spot on the media, temperature gradient and distance between the media hot spot and the write pole cannot be adequately controlled
Solution Approach 1:
The transducer is segmented into distinct functional regions: a waveguide section for light transmission, a NFT section for optical-to-thermal conversion, and a main pole section for magnetic writing. The dielectric gap physically separates the NFT from the main pole, allowing independent optimization of each segment's function and improving overall control precision.
Solution Approach 2:
A dielectric gap is introduced as an intermediary element between the NFT and the main pole. This dielectric layer mediates the interaction between the optical heating field and the magnetic field, enabling better control of the thermal profile and its alignment with the magnetic write field while preventing direct electrical contact and interference.
2Temperature
If the NFT focuses light directly to the media without a dielectric gap, then heating occurs, but the peak temperature is too far from the main pole and the thermal gradient is insufficient
Solution Approach 1:
The dielectric gap introduces a new spatial dimension (vertical separation) between the NFT and main pole. By controlling the thickness of the dielectric layer, the thermal field distribution in the vertical dimension is modified, allowing the peak temperature to be positioned at an optimal distance from the main pole while maintaining a steep thermal gradient.
Solution Approach 2:
The dielectric constant and thickness of the gap layer are adjusted as key parameters to control the thermal field distribution. By changing these parameters, the peak temperature location and thermal gradient can be optimized to achieve better alignment with the main pole for effective heat-assisted magnetic recording.
3Measurement precision
If the thermal profile is not precisely controlled, then heating occurs, but the bit matching for the reader is poor and read signal-to-noise ratios are low
Solution Approach 1:
The dielectric gap structure enables better feedback control of the thermal profile by confining the heat distribution more precisely. This improved thermal confinement provides better feedback for optimizing the write process, ensuring that the heated region aligns precisely with the magnetic transitions to be written, thereby improving both read signal quality and energy efficiency.
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 enhances the precision of the thermal profile, leading to improved writing performance by shifting the peak temperature closer to the main pole, increasing the thermal gradient, and flattening isothermal lines, which results in better bit matching for the reader and higher read signal-to-noise ratios.
Implementation Method 1
The NFT focuses the light to magnetic recording media (not shown), such as a disk. This region is thus heated.
Implementation Method 2
Light from the laser is incident on and coupled into the waveguide. Light is guided by the conventional waveguide to the NFT near the ABS.
Implementation Method 3
Incorporating a dielectric gap between the near-field transducer (NFT) and the main pole, along with a plasmonic ridge and cap, to shift the peak thermal profile closer to the main pole and increase the thermal gradient
Implementation Method 4
Incorporating a dielectric gap between the near-field transducer (NFT) and the main pole, along with a plasmonic ridge and cap, to shift the peak thermal profile closer to the main pole and increase the thermal gradient
Implementation Method 5
The main pole is energized and field from the pole tip is used to write to the heated portion of the recording media.
Data Source
AI summary
A heat assisted magnetic recording (HAMR) write apparatus coupled with a laser is described. The HAMR write apparatus includes a pole, coil(s), a near-field transducer (NFT), and a dielectric gap. The pole writes to the media. The coil(s) energize the pole. The waveguide is optically coupled with the laser and directs energy toward the ABS. The NFT is optically coupled with the waveguide and includes a metal nose and a metal cap. Part of the metal cap adjoins part of the main pole. The dielectric gap is between a first portion of the NFT and the main pole. The dielectric gap has a media-facing surface and back, top, bottom and side surfaces. The top surface adjoins the main pole. The bottom surface adjoins the first portion of the NFT. The side surfaces adjoin a second portion of the NFT. The back surface adjoins a portion of the metal cap.