Magnetic Recording Medium Seed Layer Design for High SNR
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current magnetic recording media face challenges in achieving high surface recording density and signal-noise ratio (SNR) due to difficulties in forming thin films with grains smaller than 10 nm, and existing techniques do not adequately improve magnetic characteristics or thermal stability.
Innovation Solution
A magnetic recording medium is designed with a substrate, a seed layer having an amorphous state with a metal of 2000°C or less melting point, an under layer with a hexagonal close-packed structure, and a perpendicular recording layer with a granular structure, where specific relations between saturated magnetization, gradient, thickness, and squareness ratio are satisfied to enhance SNR and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a coating method is used to apply magnetic powder on a non-magnetic support, then the magnetic recording medium can be manufactured, but it is difficult to form a thin film using fine grains having a diameter of 10 nm or less
Solution Approach 1:
The patent changes the deposition method from coating to sputtering, which allows precise control of film thickness and grain size at the nanometer scale. By using sputtering parameters (power, pressure, time) instead of coating parameters, thin films with grains ≤10 nm can be formed effectively
Solution Approach 2:
The patent uses a composite structure with multiple layers including seed layer, under layer, and magnetic recording layer. This composite approach allows each layer to be optimized independently, enabling the formation of thin films with fine grains through the seed and under layers that facilitate controlled grain growth in the magnetic recording layer
2Reliability
If the orientation of the magnetic recording layer is improved to enhance magnetic characteristics, then the recording capacity increases, but the structural complexity and manufacturing difficulty increase
Solution Approach 1:
The patent introduces a seed layer and under layer before the magnetic recording layer to pre-establish the crystal orientation and structure. This preliminary action enables the magnetic recording layer to achieve desired orientation without requiring complex post-processing or adjustment, simplifying the overall manufacturing while improving magnetic characteristics
Solution Approach 2:
The seed layer and under layer act as intermediary layers between the substrate and the magnetic recording layer. These intermediaries facilitate controlled crystal growth and orientation of the magnetic recording layer, enabling improved magnetic characteristics through a manageable multi-layer structure rather than direct deposition on the substrate
3Quantity of substance
If the surface recording density is increased to 50 Gb/in², then the recording capacity per cartridge increases, but the signal-noise ratio deteriorates
Solution Approach 1:
The patent creates local quality variations through the granular structure of the magnetic recording layer, where magnetic grains are separated by non-magnetic boundaries. This local differentiation allows each grain to maintain stable magnetization (reducing noise) while the overall high density of grains achieves 50 Gb/in² recording capacity
Solution Approach 2:
The magnetic recording layer has a granular structure with non-magnetic boundaries between magnetic grains, creating a porous-like structure at the nanoscale. This structure isolates magnetic domains, preventing magnetic interaction between grains that would cause noise, while maintaining high recording density through fine grain distribution
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 proposed structure achieves a high SNR of 20 dB or more and low output attenuation, enabling a surface recording density of 50 Gb/in² and thermal stability, significantly improving magnetic recording capabilities.
Implementation Method 1
a magnetic recording medium in which an amorphous layer, a seed layer, an under layer, a magnetic layer, and a protective layer are at least sequentially laminated on a substrate
Data Source
AI summary
A magnetic recording medium includes a substrate, a seed layer, an under layer, and a perpendicular recording layer having a granular structure. (Ms·αδ1.5(1−Rs)0.33), Ms, and α satisfy (Ms·α·δ1.5(1−Rs)0.33)≤0.1 [μ·emu·(mm)−1.5], Ms≥450 [emu/cc], and α≥1.2. In the above formulas, Ms indicates a saturated magnetization amount, α indicates the gradient of a M-H loop around a coercive force Hc, δ indicates the thickness of the perpendicular recording layer, and Rs indicates a squareness ratio.