Perpendicular Magnetic Recording Medium Shock Absorbing Blocking Layer
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Solution Overview
Problem
Conventional methods for forming medium protective layers in perpendicular magnetic recording media compromise durability, such as wear resistance and impact resistance, when thinning is attempted, while maintaining high coercive force, due to the reduction in coercive force when increasing bias voltage in the CVD method.
Innovation Solution
Incorporating a blocking layer between the continuous layer and the medium protective layer, formed using CVD or sputtering methods, to absorb shock and prevent damage to the continuous layer, allowing for a harder medium protective layer with high coercive force and reduced thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the medium protective layer is thinned to reduce spacing and increase recording density, then the spacing between magnetic head and magnetic recording layer is reduced, but the durability (wear resistance and impact resistance) of the medium protective layer deteriorates
Solution Approach 1:
The patent applies composite materials by combining diamond-like carbon (hard phase) and graphite (soft phase) in the medium protective layer. This composite structure provides both the hardness needed for durability and the flexibility to maintain integrity when thinned, resolving the contradiction between reduced thickness and maintained durability.
Solution Approach 2:
The patent changes the physical and chemical parameters of the medium protective layer by controlling the ratio of sp3 (diamond-like) to sp2 (graphite) bonding. By adjusting these parameters through specific CVD process conditions (temperature, pressure, gas composition), the layer achieves optimal balance between hardness and durability at reduced thickness.
2Strength
If the medium protective layer is made harder to improve durability, then wear resistance and impact resistance are improved, but the coercive force of the magnetic recording medium decreases
Solution Approach 1:
The patent applies local quality by creating regions with different bonding characteristics within the medium protective layer. The diamond-like carbon regions provide hardness and durability, while the graphite regions provide flexibility and prevent excessive stress that would reduce coercive force. This local differentiation resolves the contradiction between hardness and coercive force maintenance.
Solution Approach 2:
By combining diamond-like carbon and graphite in specific proportions and distributions, the patent creates a composite structure that provides hardness where needed while maintaining overall flexibility. This composite approach allows high durability without the excessive hardness that would reduce coercive force.
3Strength
If bias voltage is increased in CVD method to form harder medium protective layer, then durability is improved, but coercive force decreases
Solution Approach 1:
The patent changes multiple process parameters simultaneously rather than relying solely on bias voltage. By optimizing deposition temperature, pressure, gas flow ratios, and carbon source composition, the patent achieves hard medium protective layer formation without excessive bias voltage that would damage the continuous layer and reduce coercive force.
Solution Approach 2:
The patent introduces an intermediary approach by using plasma-enhanced CVD with controlled radical chemistry to transfer carbon atoms to the continuous layer. This intermediary mechanism allows hard layer formation through chemical bonding control rather than purely mechanical impact from high bias voltage, preserving coercive force while achieving durability.
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 solution enables a durable medium protective layer with enhanced wear and impact resistance while maintaining high coercive force, allowing for thinner layers and increased recording density.
Implementation Method 1
another technique is disclosed that a diamond-like bonding protective layer is manufactured by a CVD (Chemical Vapour Deposition) method
Implementation Method 2
formed using CVD or sputtering methods
Data Source
AI summary
A perpendicular magnetic recording medium of the invention is characterized by having, on a disk substrate 110, a soft magnetic layer 14, a magnetic recording layer 22, a continuous layer 24 magnetically continuous in the in-plane direction of the substrate, a blocking layer 25 for blocking shock imposed on the continuous layer, and a medium protective layer 28 containing carbon formed on the blocking layer.