Granular Ru Oxide Orientation Control Layer for Magnetic Media
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Solution Overview
Problem
Current methods for manufacturing magnetic recording media face challenges in achieving high recording density while maintaining sufficient surface hardness and low surface roughness, leading to reliability issues and poor adaptability to high recording densities due to the trade-off between sputtering gas pressure and crystallinity of the Ru layer.
Innovation Solution
A method involving the formation of a granular orientation control layer with Ru and an oxide having a melting point between 450°C and 1000°C, using a sputtering method at specific pressures to create a smooth surface with columnar crystal growth, which enhances the separation of crystal grains and miniaturization of magnetic particles, thereby improving surface hardness and reducing surface roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If sputtering is performed at high gas pressure to form the Ru layer, then the crystallinity and orientation of the Ru layer are improved, but the surface hardness decreases and surface roughness increases
Solution Approach 1:
The patent applies parameter changes by controlling the sputtering gas pressure within a specific range (3-10 Pa) to optimize the balance between crystallinity and surface hardness. This parameter optimization allows the Ru layer to achieve both good crystalline structure and sufficient surface hardness, resolving the contradiction between these two properties.
2Stability of the object's composition
If sputtering is performed at high gas pressure to form the Ru layer, then the orientation of the Ru layer is improved, but the surface roughness increases
Solution Approach 1:
The patent optimizes the sputtering gas pressure parameter to a specific range (3-10 Pa) that simultaneously achieves good layer orientation and maintains low surface roughness. This parameter control prevents excessive roughness while ensuring proper crystalline orientation.
3Strength
If the Ru layer is formed at low sputtering pressure to maintain surface hardness, then the crystallinity and orientation are reduced, but this limits the miniaturization of magnetic particles
Solution Approach 1:
The patent identifies and controls the sputtering gas pressure within the optimal range of 3-10 Pa, which simultaneously achieves sufficient surface hardness and good crystallinity for magnetic particle miniaturization. This precise parameter control resolves the contradiction between maintaining hardness and achieving miniaturization.
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
The approach results in a magnetic recording medium with high surface scratch resistance, reliable performance, and adaptability to high recording densities, as evidenced by a signal-to-noise ratio suitable for high-density recording and a surface roughness of 3 angstroms or less.
Implementation Method 1
forming a granular layer having a granular structure that includes Ru or a material in which Ru is a main component and an oxide having a melting point which is greater than or equal to 450° C. and less than or equal to 1000° C., by a sputtering method
Implementation Method 2
growing crystal grains to form columnar crystals that are continuous in a thickness direction together with crystal grains that form the orientation control layer
Data Source
AI summary
A method of manufacturing a magnetic recording medium, includes at least: forming an orientation control layer 3 that controls orientation of an immediately above layer thereof on a non-magnetic substrate 1; and forming a perpendicular magnetic layer 4 in which an easy axis of magnetization is mainly perpendicularly orientated to the non-magnetic substrate 1, in which the forming of the orientation control layer 3 includes forming a granular layer having a granular structure that includes Ru or a material in which Ru is a main component and an oxide having a melting point which is greater than or equal to 450° C. and less than or equal to 1000° C., by a sputtering method, and the forming of the perpendicular magnetic layer 4 includes growing crystal grains to form columnar crystals that are continuous in a thickness direction together with crystal grains that form the orientation control layer 3.