Magnetic Disk Assist Elements for Coercive Force Control
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Solution Overview
Problem
Current magnetic disk devices face challenges in achieving high recording density and capacity due to limitations in coercive force manipulation, particularly in high-frequency and thermally assisted recording techniques, where multiple assist elements complicate the control of coercive forces for efficient data writing.
Innovation Solution
A magnetic disk device configuration that includes a main magnetic pole, a write shield, and multiple assist elements with different characteristics, such as materials or thicknesses, to generate distinct assist energies, allowing for precise control of coercive forces through a controller that applies varying assist currents or voltages to improve write performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple assist elements are used to manipulate coercive force, then recording density and capacity can be increased, but device complexity and control difficulty increase
Solution Approach 1:
The assist elements are segmented into different types (first assist element and second assist element) with different characteristics, allowing independent control of coercive force in different regions of the magnetic disk, thereby increasing recording density while maintaining manageable control complexity through modular segmentation
Solution Approach 2:
Different assist elements are applied to different regions of the magnetic disk with locally optimized characteristics, where each assist element is tailored to provide appropriate assist energy for its specific region, enabling increased recording density through localized coercive force manipulation
2Measurement precision
If multiple assist elements with different characteristics are used, then coercive force control precision is improved, but device complexity increases
Solution Approach 1:
The assist elements differ in key parameters such as material composition and thickness, allowing precise control of coercive force by selecting elements with appropriate parameter values for different recording regions, achieving high control precision through parameter optimization rather than structural complexity
Solution Approach 2:
Different assist elements are made from composite materials or materials with different magnetic properties, enabling precise manipulation of coercive force through material selection rather than complex structural arrangements, thereby improving control precision while limiting structural complexity
3Productivity
If assist energy is increased to improve write performance, then data writing efficiency is improved, but energy consumption increases
Solution Approach 1:
Assist energy is applied locally and selectively to only those regions of the magnetic disk where it is needed for successful writing, rather than uniformly across the entire disk surface, thereby improving data writing efficiency while minimizing overall energy consumption through localized energy application
Solution Approach 2:
The assist energy is applied at optimal levels - sufficient to overcome coercive force where needed but not excessive - by selecting appropriate assist elements and controlling their activation, achieving high writing efficiency while avoiding unnecessary energy consumption through precise energy dosing
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 data writing efficiency by adjusting coercive forces, reducing fringe data generation and improving data quality by optimizing assist energy application based on overwrite direction, thereby increasing recording density and capacity.
Implementation Method 1
a high-frequency magnetic field that is generated by applying a current to a high-frequency oscillator is applied to a disk
Implementation Method 2
a disk is irradiated with irradiation light emitted from a tip of a light irradiation element using a magnetic head to locally heat the disk
Data Source
AI summary
According to one embodiment, a magnetic disk device includes: a disk; a head including a main magnetic pole, a write shield that faces the main magnetic pole in a first direction and is separated from the main magnetic pole by a gap, a first assist element that is disposed in the gap and a second assist element that is disposed in the gap and is positioned relative to the first assist element in a second direction intersecting the first direction; and a controller configured to: cause a first assist energy from the first assist element to be applied to the disk and affect a coercive force of the disk; and cause a second assist energy from the second assist element to be applied to the disk and affect a coercive force of the disk, wherein the first assist energy is different from the second assist energy.