Perpendicular Magnetic Recording Medium Underlayer Structure
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Solution Overview
Problem
Current methods for increasing areal recording density in magnetic recording media face challenges in reducing crystal grain size while maintaining high crystal orientation and low noise, as conventional techniques often result in random orientation and enlarged grains, leading to increased noise and decreased signal output.
Innovation Solution
A perpendicular magnetic recording medium is developed with a multilayered underlayer structure, including a first metal underlayer, a second metal underlayer with holes, and a third metal underlayer that forms solid solutions with the first but not the second, allowing for columnar growth of crystal grains and suppression of enlargement in the in-plane direction, thereby reducing medium noise and increasing recording density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the crystal grain size is reduced to increase areal recording density, then the recording density is improved, but the crystal orientation deteriorates and becomes random, leading to increased medium noise
Solution Approach 1:
The patent applies preliminary action by forming a multilayered underlayer structure with specific crystal orientations before depositing the magnetic recording layer. The underlayer includes a first underlayer with (100) orientation and a second underlayer with (110) orientation, which are prepared in advance to guide the columnar growth of magnetic crystal grains, ensuring high crystal orientation is maintained even when grain size is reduced for high-density recording
Solution Approach 2:
The patent employs parameter changes by controlling the crystal orientation parameters of the underlayer materials and their thickness ratios. By adjusting the orientation parameters ((100) and (110) orientations) and thickness parameters of the multilayered underlayer, the patent achieves optimal conditions for columnar growth of magnetic crystal grains, maintaining high crystal orientation while enabling small grain size for increased recording density
2Quantity of substance
If the crystal grain size is reduced to increase areal recording density, then the recording density is improved, but the medium noise increases due to random crystal orientation
Solution Approach 1:
The patent applies preliminary action by forming a multilayered underlayer structure with specific crystal orientations before depositing the magnetic recording layer. The underlayer includes a first underlayer with (100) orientation and a second underlayer with (110) orientation, which are prepared in advance to guide the columnar growth of magnetic crystal grains, ensuring high crystal orientation is maintained even when grain size is reduced for high-density recording
Solution Approach 2:
The patent employs parameter changes by controlling the crystal orientation parameters of the underlayer materials and their thickness ratios. By adjusting the orientation parameters ((100) and (110) orientations) and thickness parameters of the multilayered underlayer, the patent achieves optimal conditions for columnar growth of magnetic crystal grains, maintaining high crystal orientation while enabling small grain size for increased recording density
3Length of moving object
If conventional thin film stacking methods are used to reduce grain size, then the grain size is naturally reduced, but the grain size cannot be unconditionally controlled and often becomes enlarged
Solution Approach 1:
The patent applies preliminary action by forming a multilayered underlayer structure with specific crystal orientations before depositing the magnetic recording layer. The underlayer includes a first underlayer with (100) orientation and a second underlayer with (110) orientation, which are prepared in advance to guide the columnar growth of magnetic crystal grains, ensuring high crystal orientation is maintained even when grain size is reduced for high-density recording
Solution Approach 2:
The patent employs parameter changes by controlling the crystal orientation parameters of the underlayer materials and their thickness ratios. By adjusting the orientation parameters ((100) and (110) orientations) and thickness parameters of the multilayered underlayer, the patent achieves optimal conditions for columnar growth of magnetic crystal grains, maintaining high crystal orientation while enabling small grain size for increased recording density
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 approach effectively reduces medium noise and enhances areal recording density by maintaining a high degree of crystal orientation and small crystal grain size, improving signal-to-noise ratios for high-density recording.
Implementation Method 1
a third metal underlayer which forms solid solutions with the first metal underlayer
Data Source
AI summary
In a perpendicular magnetic recording medium, a multilayered underlayer including a first metal underlayer, a second metal underlayer having no solid solution properties with respect to the first metal underlayer and having a hole, and a third metal underlayer having solid solution properties with respect to the first metal underlayer and having no solid solution properties with respect to the second metal underlayer is formed on a substrate, and a magnetic recording layer is formed on the multilayered underlayer.