Perpendicular Magnetic Recording Medium Grain Isolation
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Solution Overview
Problem
The challenge in achieving higher recording density in perpendicular magnetic recording media is the degradation of coercive force and signal-to-noise ratio due to excessive oxide content in the grain boundary, which limits the separation and isolation of magnetic grains, affecting thermal stability and noise levels.
Innovation Solution
Incorporating a common oxide in the non-magnetic granular layer and magnetic recording layer with a granular structure, where the oxides in the grain boundary parts are of the same composition, enhances the affinity between interfaces, promoting continuous growth and further separation of magnetic grains, thereby improving electromagnetic and magnetostatic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the amount of oxide in the grain boundary is increased to separate and isolate magnetic grains, then the SNR is improved, but the coercive force Hc and perpendicular magnetic anisotropy are degraded
Solution Approach 1:
The patent applies local quality by creating a non-magnetic granular layer with a specific granular structure between the Ru ground layer and the magnetic recording layer. This layer has localized non-magnetic regions (oxides) that provide separation at the interface, while maintaining magnetic properties in the bulk of the magnetic recording layer. The granular structure with non-magnetic substances in grain boundaries creates local isolation effects without compromising the overall magnetic strength.
Solution Approach 2:
The patent uses composite materials by combining magnetic particles with non-magnetic substances (oxides) to form a granular structure. This composite approach allows the magnetic recording layer to have both magnetic properties (from the magnetic particles) and separation/isolation properties (from the non-magnetic oxide regions), resolving the contradiction between needing high coercive force and high SNR.
2Measurement precision
If the amount of oxide in the grain boundary is increased to separate and isolate magnetic grains, then the SNR is improved, but thermal stability is degraded
Solution Approach 1:
The non-magnetic granular layer provides localized oxide segregation at the interface region, creating local separation effects where needed without compromising the thermal stability of the bulk magnetic recording layer. The magnetic particles in the main recording layer maintain their thermal stability while the interface layer provides the necessary isolation for high SNR.
Solution Approach 2:
The non-magnetic granular layer acts as an intermediary layer between the Ru ground layer and the magnetic recording layer. This intermediate structure provides oxide segregation for separation and isolation without directly affecting the thermal stability of the magnetic recording layer, as the intermediary layer buffers the interaction between the ground layer and magnetic layer.
3Measurement precision
If a non-magnetic granular layer is formed on the Ru ground layer to promote separation, then magnetic particle isolation is improved, but crystal orientation is broken and coupling occurs
Solution Approach 1:
The patent changes the structural parameters by creating a granular structure with specific grain boundary characteristics. By controlling the oxide segregation and grain boundary formation in the non-magnetic granular layer, the patent maintains crystal orientation while achieving separation. The granular structure parameters are optimized to prevent coupling while preserving orientation.
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
This approach increases the separation and isolation of magnetic grains, enhancing the signal-to-noise ratio and coercive force, leading to increased recording density and thermal stability while maintaining optimal oxide content.
Implementation Method 1
a non-magnetic granular layer having a granular structure in which a grain boundary part including one or a plurality of oxides is formed between non-magnetic grains
Implementation Method 2
magnetic particles are epitaxially grown to form a granular structure in a columnar shape
Data Source
AI summary
An object of the present invention is to increase an electromagnetic transducing characteristic (in particular, SNR) by further promoting separation and isolation of magnetic grains of a magnetic recording layer (122) in a perpendicular magnetic recording medium (100). Thus, a typical structure of the perpendicular magnetic recording medium (100) according to the present invention includes, on a substrate (110), at least a non-magnetic granular layer (120) having a granular structure in which a grain boundary part including one or a plurality of oxides is formed between non-magnetic grains each continuously grown in a columnar shape and a magnetic recording layer (122) formed continuously with the non-magnetic granular layer (120) and having a granular structure in which a grain boundary part including one or a plurality of oxides is formed between magnetic grains continuously grown in a columnar shape in this order, and at least one oxide included in the grain boundary part of the non-magnetic granular layer (120) and at least one oxide included in the grain boundary part of the magnetic recording layer (122) are oxides of a same composition.