Co-Pt Sputtering Target Composition for Magnetic Grain Separation
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Solution Overview
Problem
Existing magnetic layers in hard disk drives face challenges in achieving high magnetic anisotropy and thermal stability while maintaining high magnetic separation between particles, as excessive addition of metal oxides can deteriorate crystallinity and reduce magnetic properties.
Innovation Solution
Incorporating Nb2O5 as a metal oxide in a Co—Pt alloy sputtering target, either alone or in combination with TiO2, to improve magnetic separation without significantly lowering magnetic anisotropy, by forming a stable oxide that reduces magnetic interaction between grains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a large amount of metal oxide is added to improve magnetic separation, then magnetic separation between particles is improved, but the metal oxide enters magnetic particles and deteriorates crystallinity, thereby decreasing saturation magnetization and magnetic anisotropy
Solution Approach 1:
The patent changes the chemical composition parameter by replacing conventional SiO2 with Nb2O5 as the metal oxide. Nb2O5 has different physical and chemical properties including higher melting point and different surface characteristics, which allow it to remain at grain boundaries without penetrating into magnetic particles, thus improving magnetic separation while preserving crystallinity and magnetic properties.
Solution Approach 2:
The patent creates a composite structure where Nb2O5 particles are dispersed at the grain boundaries of the Co-Pt magnetic particles. This composite arrangement forms a nonmagnetic barrier layer that separates magnetic domains effectively without compromising the internal crystalline structure of the magnetic particles, achieving both high magnetic separation and maintained magnetic properties.
2Manufacturing precision
If a large amount of metal oxide is added to improve magnetic separation, then magnetic separation between particles is improved, but magnetic anisotropy is decreased
Solution Approach 1:
The patent changes the oxide composition from SiO2 to Nb2O5, which has different interaction characteristics with the Co-Pt magnetic matrix. Nb2O5 maintains magnetic anisotropy by forming a stable interface with the magnetic particles and preventing oxide penetration that would disrupt the magnetocrystalline anisotropy, while still providing effective magnetic separation at grain boundaries.
3Ease of manufacture
If conventional SiO2 is used as metal oxide, then the magnetic layer can be formed, but magnetic separation is insufficient and excessive SiO2 adds enters magnetic particles deteriorating crystallinity
Solution Approach 1:
The patent changes the oxide material parameter from SiO2 to Nb2O5. Nb2O5 has superior performance in this application due to its ability to remain as discrete particles at grain boundaries without dissolving or penetrating into the magnetic phase, providing better magnetic separation than SiO2 while maintaining ease of formation through standard sputtering processes.
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 use of Nb2O5 and TiO2 in the sputtering target allows for enhanced magnetic separation and maintained high magnetic anisotropy and saturation magnetization, effectively addressing the limitations of previous technologies.
Implementation Method 1
each layer such as the magnetic layer and the intermediate layer is formed by sputtering a material onto a substrate using a sputtering target
Implementation Method 2
Nb2O5 has reasonable wettability to Co and can form a stable oxide even if a part of oxygen is lacked
Data Source
AI summary
A sputtering target according to the present invention contains Co and Pt as metal components, wherein a molar ratio of a content of Pt to a content of Co is from 5/100 to 45/100, and wherein the sputtering target contains Nb2O5 as a metal oxide component.