Sloped Pole Piece for HAMR Head Waveguide
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Solution Overview
Problem
In heat-assisted magnetic recording, positioning magnetic poles relative to a waveguide is challenging due to magnetic materials being poor optical materials, leading to issues like adjacent track writing and data destabilization.
Innovation Solution
A magnetic pole design with a sloped pole piece that extends from a first portion spaced from the waveguide to the air bearing surface, where the second portion is closer to the waveguide, allowing for varying magnetic saturation and cross-sectional shapes, and includes a protrusion for improved magnetic field control, along with a near field transducer in the waveguide core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If magnetic poles are positioned close to the waveguide to improve magnetic field strength, then magnetic recording performance is improved, but adjacent track writing and data destabilization occur due to poor optical properties of magnetic materials
Solution Approach 1:
The first pole is divided into two portions: a first portion spaced from the waveguide and a second portion extending from the first portion to the air bearing surface with the second portion being closer to the waveguide. This segmentation allows different parts of the same pole to serve different functions - the first portion maintains optical compatibility while the second portion provides enhanced magnetic field strength near the recording interface.
Solution Approach 2:
The second portion of the first pole has varying magnetic saturation in the down track direction, either discretely using layers having different magnetic saturation or continuously. This local quality variation optimizes the magnetic field distribution precisely where needed at the air bearing surface while maintaining compatibility with the waveguide structure.
2Manufacturing precision
If magnetic materials are positioned in close proximity with the waveguide to enhance magnetic field control, then recording precision is improved, but optical performance deteriorates due to poor optical properties of magnetic materials
Solution Approach 1:
The pole structure is segmented into portions at different distances from the waveguide. The first portion is spaced from the waveguide to maintain optical performance, while the second portion extends closer to provide enhanced magnetic field control at the air bearing surface, thus resolving the contradiction between optical and magnetic requirements.
Solution Approach 2:
The solution moves the magnetic pole structure into a different spatial configuration by extending the second portion in the vertical dimension toward the air bearing surface while maintaining horizontal spacing from the waveguide. This dimensional arrangement allows simultaneous optimization of both optical path clearance and magnetic field strength at the recording interface.
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 design reduces the probability of adjacent track writing and data destabilization by optimizing magnetic field distribution, enhancing the precision and stability of heat-assisted magnetic recording.
Implementation Method 1
a beam of light is condensed to a small optical spot onto the storage medium to heat a portion of the medium
Implementation Method 2
heat a portion of the medium and reduce the magnetic coercivity of the heated portion
Implementation Method 3
an applied magnetic writing field can more easily direct the magnetization of the storage medium
Implementation Method 4
direct the magnetization of the storage medium during the temporary magnetic softening of the storage medium
Implementation Method 5
The magnetic saturation of the second portion of the first pole can vary in a down track direction, either discretely using layers having different magnetic saturation, or continuously
Data Source
AI summary
An apparatus includes a waveguide having an end adjacent to an air bearing surface, first and second poles positioned on opposite sides of the waveguide, and wherein the first pole includes a first portion spaced from the waveguide and a second portion extending from the first portion to the air bearing surface, with the second portion being structured such that an end of the second portion is closer to the waveguide than the first portion.