Ni Alloy Seed Layer for Perpendicular Recording Media
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Solution Overview
Problem
Conventional perpendicular magnetic recording media are not rigid enough to withstand sheer stress from hard particles, leading to physical and irreversible magnetic damage, and the high cost of Ru-based layers makes thinner alternatives desirable.
Innovation Solution
A perpendicular magnetic recording medium is developed using a Ni alloy seed layer with a FCC crystalline structure, allowing for thinner Ru-based interlayers and enhanced mechanical stability, comprising a substrate, a Ni alloy seed layer, and interlayers that promote perpendicular crystal growth and increased scratch resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional perpendicular media structure is used, then magnetic recording function is achieved, but the media is not rigid enough to withstand sheer stress from hard particles
Solution Approach 1:
The patent changes the material composition parameter of the seed layer from conventional amorphous Ta or FCC Cu/Au/Ag to a Ni-based alloy with specific composition (Ni70Pd30, Ni75Pt25, Ni75Ir25, or Ni75Rh25) and controlled thickness (5-200 Å). This parameter change transforms the mechanical properties of the entire media structure, making it rigid enough to resist scratch damage from hard particles while maintaining perpendicular magnetic anisotropy for reliable recording function.
2Strength
If Ru-based interlayers are used with sufficient thickness for structural integrity, then mechanical stability is achieved, but cost increases
Solution Approach 1:
The Ni-based seed layer fundamentally changes the crystal growth template, enabling Ru interlayers to achieve adequate mechanical stability at reduced thickness. The Ni alloy promotes perpendicular crystal orientation that propagates through the Ru layers, allowing thinner Ru deposits (while maintaining ≥200 Å total interlayer thickness) to provide sufficient structural rigidity without the high material cost of thick Ru-based layers.
3Stability of the object's composition
If conventional seed layers (amorphous Ta or FCC Cu/Au/Ag) are used, then crystal growth is achieved, but the media structure lacks rigidity
Solution Approach 1:
The patent employs composite material strategy by combining Ni-based alloy (providing mechanical rigidity and structural stability) with controlled crystal growth promotion (enabling perpendicular orientation). The Ni70Pd30, Ni75Pt25, Ni75Ir25, or Ni75Rh25 compositions create a unique composite effect where the Ni matrix provides strength while the alloying elements facilitate the desired crystallographic orientation, achieving both rigidity and crystal growth in a single seed layer.
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 a Ni alloy seed layer results in a more rigid media structure with improved scratch resistance and maintained signal-to-noise ratio, reducing physical and magnetic damage while allowing for thinner Ru-based interlayers, thus addressing the cost and durability issues of conventional media.
Implementation Method 1
Conventional seed layers are used to prepare and enhance crystal growth of the interlayers. The interlayers are normally Ru and Ru alloys which grow hcp orientations to serve as templates for perpendicular growth of magnetic alloys.
Implementation Method 2
The thin-film perpendicular magnetic recording medium comprises a substrate and a magnetic layer having perpendicular magnetic anisotropy. In perpendicular media, the magnetization of the disc, instead of lying in the disc's plane as it does in longitudinal recording, stands on end perpendicular to the plane of the disc.
Data Source
AI summary
The invention relates to a perpendicular magnetic recording medium having a substrate and a seed layer comprising a Ni alloy.