Asymmetric Magnetic Pole End Surface for Thermal-Assisted Recording
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Solution Overview
Problem
Conventional magnetic recording heads face challenges in maintaining an optimal signal-to-noise (S/N) ratio across different radial positions on a magnetic disk due to varying transducer-pole distances and peripheral speeds, leading to suboptimal medium travel time and recording performance.
Innovation Solution
The magnetic recording head features an asymmetric pole end surface of the main pole, which adjusts the distance between the heating spot center and the pole end surface based on the radial position, ensuring optimal S/N ratio by matching the medium travel time with the peripheral speed across inner, intermediate, and outer peripheral positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the transducer-pole distance is increased to improve recording density, then the recording capacity increases, but the medium travel time becomes excessively long causing suboptimal S/N ratio
Solution Approach 1:
The pole end surface is designed with an asymmetric shape relative to the longitudinal direction of the slider, creating different distances from the heating spot center to the pole end surface in the inner peripheral and outer peripheral directions. This asymmetric configuration allows the medium travel time to be adjusted and optimized for different radial positions on the disk, thereby improving the S/N ratio while maintaining high recording capacity.
2Quantity of substance
If the magnetic head is positioned at inner peripheral position to increase recording density, then the linear velocity decreases improving S/N ratio, but the transducer-pole distance increases causing excessive medium travel time
Solution Approach 1:
The asymmetric pole end surface configuration creates different effective pole lengths in the inner and outer peripheral directions. When positioned at the inner peripheral region, the shorter effective pole length compensates for the increased transducer-pole distance, maintaining optimal medium travel time and S/N ratio while achieving high recording density.
3Speed
If the magnetic head is positioned at outer peripheral position to increase linear velocity, then the peripheral speed increases improving recording speed, but the transducer-pole distance decreases causing excessively short medium travel time
Solution Approach 1:
The asymmetric pole end surface extends longer in the outer peripheral direction, creating a longer effective pole length when positioned at outer radial positions. This compensates for the reduced transducer-pole distance, ensuring the medium travel time remains optimal even at higher peripheral speeds, thereby maintaining signal quality while achieving fast recording.
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 allows for consistent optimal recording performance across all radial positions, reducing deviations in medium travel time and enhancing signal quality, thereby improving recording characteristics and achieving better S/N ratios compared to conventional designs.
Implementation Method 1
a near-field transducer, which emits near-field light toward a recording layer of the recording medium
Implementation Method 2
the medium recording layer having a perpendicular magnetic anisotropy is locally heated by the near-field light emitted from the distal end of the near-field transducer during writing data
Data Source
AI summary
According to one embodiment, a magnetic recording head includes a medium-facing surface, a near-field transducer partially exposed in the medium-facing surface, and a magnetic pole including a distal end surface and a pole end surface facing the near-field transducer. The pole end surface in the medium-facing surface is asymmetric with respect to a central axis passing through a center of the near-field transducer and extending in a longitudinal direction of the medium-facing surface.