Ru-Bi Sputtering Target for High-Density Magnetic Recording
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Solution Overview
Problem
The existing sputtering targets with added metal oxides like SiO2, TiO2, and B2O3 fail to adequately improve the separateness and crystal orientation of magnetic particles, limiting recording density in perpendicular magnetic recording media.
Innovation Solution
A sputtering target with 0.05 at % or more Bi and a total metal oxide content of 10 vol % to 70 vol %, primarily composed of Ru, is used to form a granular film that enhances particle separation and crystal orientation by suppressing particle growth and achieving uniform particle size dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal oxides are added to form a granular structure, then exchange coupling between magnetic particles is weakened, but recording density cannot be further improved
Solution Approach 1:
The patent optimizes the concentration parameters of metal oxides (1-30 at% total content) in the sputtering target to achieve the right balance between exchange coupling control and recording density. By precisely controlling the oxide content and composition, the patent achieves sufficient particle separation for high-density recording while maintaining adequate exchange coupling control for stable magnetic properties.
Solution Approach 2:
The patent creates local variations in composition by forming a granular structure where metal oxide phases are distributed among metallic phases. This local quality differentiation allows regions with different properties: areas with higher oxide content provide particle separation and reduced exchange coupling, while areas with metallic phases maintain crystal orientation and magnetic properties, enabling both exchange coupling control and high recording density.
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 effectively reduces particle size dispersion and improves separateness between magnetic particles while maintaining crystal orientation, leading to higher magnetic anisotropy and recording density in perpendicular magnetic recording media.
Implementation Method 1
Each of these layers is sputtered on a substrate using a sputtering target corresponding to each layer to form each film sequentially
Data Source
AI summary
Provided is a sputtering target containing 0.05 at % or more of Bi, and having a total content of metal oxides of from 10 vol % to 70 vol %, the balance containing at least Ru.