Diffusion Preventing Layer for Magnetic Recording Medium Corrosion
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Solution Overview
Problem
The challenge is to enhance the corrosion resistance of magnetic recording media, which is compromised when the deposition temperature of the perpendicular magnetic layer is increased, leading to diffusion of oxides and impurities that cause corrosion.
Innovation Solution
A method of manufacturing a magnetic recording medium that includes forming a diffusion preventing layer using reactive sputtering, ion implantation, or ion etching, positioned between the perpendicular magnetic layer and the protective layer, comprising components like Si, Ti, Cr, B, or Ru, or their carbides and oxides, to prevent oxide diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the deposition temperature of the perpendicular magnetic layer is increased to enhance crystal orientation and recording density, then the crystal orientation and recording density are improved, but the oxide in the perpendicular magnetic layer diffuses to the surface through heat diffusion, allowing impurities to enter and causing corrosion
Solution Approach 1:
A diffusion preventing layer is introduced as an intermediary between the perpendicular magnetic layer and the protective layer. This intermediate layer specifically blocks the diffusion path of oxide from the magnetic layer to the surface, preventing impurity entry and corrosion while allowing the high temperature deposition process to proceed for achieving good crystal orientation.
Solution Approach 2:
The structure is segmented by adding a separate diffusion preventing layer between the perpendicular magnetic layer and the protective layer. This segmentation creates a dedicated functional barrier that addresses the corrosion issue without affecting the deposition parameters of the magnetic layer, allowing independent optimization of both crystal orientation and corrosion resistance.
2Quantity of substance
If the deposition temperature of the perpendicular magnetic layer is increased to improve recording density, then the recording density is enhanced, but element diffusion occurs between layers, deteriorating the magnetic property
Solution Approach 1:
The diffusion preventing layer serves as a mediator that suppresses element diffusion between the perpendicular magnetic layer and adjacent layers during high temperature deposition. This maintains the compositional stability and magnetic properties of each layer while enabling high temperature processing needed for high recording density.
3Reliability
If a diffusion preventing layer is added to prevent oxide diffusion and improve corrosion resistance, then the corrosion resistance is enhanced, but the device complexity increases
Solution Approach 1:
The diffusion preventing layer is applied locally only where oxide diffusion occurs - between the perpendicular magnetic layer and the protective layer. This localized approach addresses the specific corrosion problem without requiring complex changes throughout the entire structure, minimizing the increase in device complexity.
Solution Approach 2:
The diffusion preventing layer is formed using composite materials with specific compositions (containing elements like Si, Ti, Cr, B, or Ru, or their carbides and oxides) that provide both diffusion barrier functionality and compatibility with adjacent layers. This allows effective corrosion protection while maintaining structural integrity and minimizing complexity.
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 implementation of the diffusion preventing layer effectively enhances the corrosion resistance of the magnetic recording medium by preventing oxide diffusion and reducing corrosion spots, thereby improving the medium's durability.
Implementation Method 1
the element constituting the perpendicular magnetic layer diffuses to other layers that constitutes the magnetic recording medium, resulting in deterioration of the magnetic property. In particular, when the oxide contained in the perpendicular magnetic layer diffuses to the surface of the magnetic recording medium by heat diffusion due to heat during manufacturing
Implementation Method 2
forming a diffusion preventing layer by a reactive sputtering method
Implementation Method 3
forming a diffusion preventing layer by a reactive sputtering method, an ion implantation method, or an ion etching method
Data Source
AI summary
A method of manufacturing a magnetic recording medium including: forming a diffusion preventing layer, wherein the magnetic recording medium includes a non-magnetic substrate; an underlayer; a perpendicular magnetic layer; the diffusion preventing layer; and a protective layer, wherein the perpendicular magnetic layer has a multi-layer structure, the perpendicular magnetic layer includes an uppermost layer and at least one layer other than the uppermost layer, the uppermost layer including Co or Fe in magnetic particles, and the at least one layer other than the uppermost layer including an oxide, the diffusion preventing layer is provided between the perpendicular magnetic layer and the protective layer, and the diffusion preventing layer includes at least one component selected from a group consisting of Si, Ti, Cr, B, and Ru, or either a carbide, an oxide, or both, of the at least one component.