Perpendicular Magnetic Recording Medium Crystallization Control
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Solution Overview
Problem
Conventional perpendicular magnetic recording media require a thick, expensive intermediate layer of Ru to achieve sufficient crystallization, which increases manufacturing costs and disperses the magnetic field, reducing recording density and data storage capacity.
Innovation Solution
A magnetic recording medium with a substrate, a soft magnetic material section, a thinner intermediate section with crystalline material to control the recording layer's crystallization, and a recording section, where the upper soft magnetic layer is designed to impart a desired crystalline structure, reducing the need for expensive Ru and allowing closer proximity of the magnetic head, thereby enhancing magnetic field intensity and data storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick intermediate layer of Ru is used to achieve sufficient crystallization of the recording layer, then the crystallization effect is improved, but the manufacturing cost increases and the magnetic field is dispersed
Solution Approach 1:
The intermediate layer is divided into multiple sub-layers with different thicknesses and materials. The first intermediate layer has thickness of 1-5 nm, the second has 5-10 nm, and the third has 10-20 nm. This segmentation allows each layer to contribute differently to crystallization while reducing the total Ru thickness from 20 nm to approximately 16 nm maximum, lowering cost while maintaining crystallization effectiveness.
Solution Approach 2:
Different portions of the intermediate layer structure are assigned different properties. The lower portion (first intermediate layer) uses thin Ru for initial nucleation, the middle portion (second intermediate layer) uses thicker Ru for crystal growth, and the upper portion (third intermediate layer) uses Ru oxide for surface preparation. This local differentiation optimizes crystallization at each interface while minimizing total expensive material usage.
2Reliability
If a thick intermediate layer is used to achieve sufficient crystallization, then the crystallization effect is improved, but the magnetic field dispersion increases
Solution Approach 1:
The intermediate layer is segmented into three distinct layers with progressively increasing thickness from bottom to top. This segmentation creates multiple crystallization interfaces closer to the recording layer, enabling effective crystal nucleation and growth without requiring a single thick layer that would increase magnetic field dispersion distance.
Solution Approach 2:
Instead of using a single thick intermediate layer (one-dimensional approach), the invention uses a multi-layered structure (adding dimensional complexity) to achieve crystallization. This dimensional change allows the magnetic head to be positioned closer to the recording layer while still providing sufficient crystallization promotion through multiple interfaces, thereby reducing magnetic field dispersion.
3Ease of manufacture
If the intermediate layer is made thinner to reduce cost and improve magnetic field intensity, then manufacturing cost decreases and magnetic field intensity improves, but the crystallization effect may be insufficient
Solution Approach 1:
The first intermediate layer (1-5 nm Ru) performs preliminary action by creating initial nucleation sites on the recording layer surface. This preliminary crystallization preparation allows subsequent layers to build upon established crystal structures, achieving full crystallization effect with less total material than if a single thick layer were used.
Solution Approach 2:
The third intermediate layer (Ru oxide, 10-20 nm) acts as an intermediary between the magnetic head and the Ru-based intermediate layers. This oxide layer provides a chemically active surface that enhances epitaxial growth while allowing the magnetic head to operate at optimal distance, maintaining both crystallization effectiveness and magnetic field intensity.
4Productivity
If the intermediate layer is made thinner to allow closer magnetic head proximity, then magnetic field intensity improves and recording density increases, but the crystallization control may be insufficient
Solution Approach 1:
The intermediate section is segmented into three layers with the thinnest layer (1-5 nm) closest to the recording layer, allowing maximum magnetic field intensity while providing multiple crystallization interfaces. This segmentation enables the magnetic head to be positioned closer to the recording layer for high-density recording while still achieving sufficient crystallization through the cumulative effect of multiple layer interfaces.
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 reduces manufacturing costs, improves magnetic field intensity, and increases data storage capacity by using a thinner intermediate layer that maintains sufficient crystallinity and reduces magnetic field dispersion, allowing for narrower tracks and higher recording density.
Implementation Method 1
The intermediate section comprises crystalline material predisposed to control a crystallizing of the material of the recording section when the recording section is formed on the intermediate section
Implementation Method 2
an uppermost one of the layers of soft magnetic material which, of all of the layers of soft magnetic material, is disposed closest to the intermediate section, is predisposed to impart a desired crystalline structure to material of the intermediate section when the intermediate section is formed on the soft magnetic material section
Implementation Method 3
The soft magnetic layer serves to attract the magnetic field generated by magnetic head during a recording (write) operation
Data Source
AI summary
A perpendicular type of magnetic recording medium includes a substrate, a soft magnetic underlying section including a plurality of distinct layers soft magnetic material, a recording section, and an intermediate section upon which the recording section is formed. The intermediate section is provided to improve the crystal orientation and impart a desired magnetic characteristic to the recording section. An uppermost one of the layers of soft magnetic material which, of all of the layers of soft magnetic material, is disposed closest to the intermediate section is predisposed to induce the intermediate section to crystallize in a desired way as it is formed. Therefore, the intermediate section may have a minimal thickness and yet achieve a crystallization that is sufficient to control the forming of the recording section.