Soft Magnetic Underlayer for High-Density Recording Media
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current magnetic recording media face challenges in achieving high Signal-to-Noise Ratio (SNR) and overwrite characteristics, which are difficult to satisfy with existing methods of adding grain boundary materials and providing soft magnetic underlayers, especially when using high-Ku materials like L10 type FePt alloys.
Innovation Solution
A magnetic recording medium is designed with a substrate, a magnetic layer having an L10 type crystal structure, and multiple underlayers, including a soft magnetic underlayer with a hexagonal close-packed structure containing Co metal or Co as the main component, oriented with a (11•0) plane parallel to the substrate surface, along with orientation control underlayers and a heat barrier layer to enhance SNR and overwrite performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If grain boundary material is added to the magnetic layer, then medium SNR is improved, but device complexity increases
Solution Approach 1:
The patent introduces a soft magnetic underlayer as an intermediary component between the substrate and the magnetic layer. This underlayer mediates the magnetic field distribution and reduces medium noise, achieving high medium SNR without modifying the magnetic layer itself, thus avoiding the complexity of adding grain boundary materials to the magnetic layer structure.
2Reliability
If a soft magnetic underlayer is provided, then overwrite characteristic is improved, but device complexity increases
Solution Approach 1:
The soft magnetic underlayer is designed to perform multiple functions simultaneously: it improves overwrite characteristics by providing magnetic field assistance, reduces medium noise to enhance SNR, and facilitates the formation of the magnetic layer structure. This multi-functionality achieves reliability improvement without proportionally increasing device complexity.
3Stability of the object's composition
If substrate is heated to 500°C or higher, then L10 type crystal structure ordering is improved, but material selection for soft magnetic underlayer becomes more restricted
Solution Approach 1:
The patent specifies particular material compositions and crystallographic orientations for the soft magnetic underlayer that are stable at high temperatures. By carefully selecting materials with appropriate thermal stability parameters and controlling their crystal orientation, the system achieves L10 type crystal structure ordering at 500°C or higher while maintaining underlayer functionality.
4Productivity
If magnetic grain size is reduced, then surface recording density is increased, but thermal stability becomes more difficult to maintain
Solution Approach 1:
The patent employs a composite structure consisting of the soft magnetic underlayer with specific magnetic properties and the magnetic layer with high-Ku material. This composite structure allows the magnetic layer to have fine grain size for high recording density while the underlayer provides thermal stability and magnetic field assistance, enabling both high productivity and thermal stability.
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 configuration significantly improves the medium SNR and overwrite characteristics, achieving high recording densities and reducing medium noise, while maintaining thermal stability and compatibility with both heat-assisted and microwave-assisted recording methods.
Implementation Method 1
at least one of the plurality of underlayers is a soft magnetic underlayer formed by an alloy having a hexagonal close packed (hcp) structure and including Co metal or Co as its main component, with a (11•0) plane oriented parallel to a surface of the substrate
Implementation Method 2
a magnetic layer including an alloy having an L10 type crystal structure
Implementation Method 3
a magnetic layer including an alloy having an L10 type crystal structure
Implementation Method 4
a heat barrier layer to enhance SNR and overwrite performance
Data Source
AI summary
A magnetic recording medium includes a substrate, a magnetic layer including an alloy having an L10 type crystal structure, and a plurality of underlayers arranged between the substrate and the magnetic layer. At least one of the plurality of underlayers is a soft magnetic underlayer formed by an alloy having a hexagonal close packed (hcp) structure and including Co metal or Co as its main component, with a (11•0) plane oriented parallel to a surface of the substrate.