Magnetic Recording Underlayer for Heat-Assisted Media Orientation
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Solution Overview
Problem
Conventional heat-assisted magnetic recording media struggle to achieve sufficient (001) orientation of the magnetic layer, leading to inadequate signal-to-noise ratio (SNR) due to insufficient underlayer performance in controlling magnetic recording characteristics and heat spot expansion.
Innovation Solution
A magnetic recording medium is designed with a substrate, an underlayer containing Al, Ag, Cu, or Mo as main components, and a magnetic layer with an L10 type crystal structure, where the underlayer includes a crystalline layer with a non-granular structure and a barrier layer to enhance (001) orientation and suppress heat spot expansion, thereby improving SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional underlayer materials (MgO, CrN, TiN) are used, then the magnetic layer can be formed, but the (001) orientation of the magnetic layer is insufficient
Solution Approach 1:
The patent changes the material composition parameters of the underlayer by incorporating specific elements (Ta, W, Mo, Al, Si) in controlled amounts to optimize the crystal orientation. The underlayer contains these elements in specific concentration ranges to promote (001) orientation of the L10-type magnetic layer, directly resolving the orientation insufficiency of conventional underlayer materials
Solution Approach 2:
The patent creates a composite underlayer material combining multiple elements (MgO base with Ta, W, Mo, Al, Si additions) to achieve superior (001) orientation control. This composite approach leverages the synergistic effects of different elements to enhance crystal orientation and reduce noise, improving the signal-to-noise ratio
2Reliability
If the magnetic layer is miniaturized to increase storage density, then the signal-to-noise ratio improves, but thermal fluctuation increases
Solution Approach 1:
The patent utilizes heat-assisted magnetic recording by controlling temperature parameters during the recording process. The magnetic head irradiates the magnetic layer with near-field light to locally heat the surface, temporarily reducing coercivity for writing, then allowing rapid cooling to stabilize the magnetic state. This temperature control enables miniaturization while managing thermal effects
3Reliability
If the underlayer is designed to control heat spot expansion, then noise is reduced, but the complexity of the underlayer structure increases
Solution Approach 1:
The patent controls heat spot expansion by adjusting the thermal conductivity parameters of the underlayer through material composition. The underlayer contains elements with specific thermal properties that regulate heat diffusion, narrowing the magnetic transition area in the planar direction and reducing noise without requiring complex multi-layer structures
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 enhances the signal-to-noise ratio (SNR) by promoting (001) orientation of the magnetic layer and reducing noise through effective heat management, resulting in improved magnetic recording density and characteristics.
Implementation Method 1
an underlayer that is able to enhance the (001) orientation of a magnetic layer of a heat-assisted magnetic recording medium
Implementation Method 2
the expansion of the heat spot needs to be suppressed such that a magnetic transition area is narrowed in a planar direction and noise is reduced
Implementation Method 3
a magnetic head irradiates a magnetic recording medium with near-field light to partially heat the surface of the magnetic recording medium, such that the coercivity of the magnetic recording medium can be reduced
Data Source
AI summary
A magnetic recording medium includes: a substrate; an underlayer; and a magnetic layer including an alloy having a L10 type crystal structure whose plane orientation is (001). The substrate, the underlayer, and the magnetic layer are stacked in this order. The underlayer includes a first underlayer. The first underlayer is a crystalline layer that includes a material containing Al, Ag, Cu, W, or Mo as a main component element and includes an oxide of the main component element, a content of the oxide of the main component element in the first underlayer being in a range of from 2 mol % to 30 mol %.