Magnetic Recording Medium Seed Layer Grain Pitch Control
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Solution Overview
Problem
The granular-type recording layer in magnetic recording media experiences increased transition noise and jitter noise due to reduced magnetic exchange interaction between magnetic grains, limiting the minimum bit size and recording density, which is challenging to improve without compromising corrosion resistance and grain pitch distribution.
Innovation Solution
A magnetic recording medium with a non-magnetic seed layer composed of Ag particles, Ge grain boundaries, and a compound X (oxide, nitride, or carbide of Al, Ti, Cr, Si, and Ta) is used, improving grain pitch distribution and corrosion resistance by distributing the compound X within the Ag particles and Ge grain boundaries, and continuing this structure to the perpendicular magnetic recording layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a granular-type recording layer is used to reduce magnetic exchange interaction between grains, then transition noise is reduced and limit bit size is reduced, but the distribution of inverse magnetic field increases causing increase of transition noise and jitter noise
Solution Approach 1:
The patent applies local quality by creating a dual-structure recording layer where magnetic crystal grains are two-dimensionally isolated by non-magnetic grain boundary regions. This local differentiation allows each grain to maintain independent magnetic properties while collectively reducing noise through the non-magnetic boundaries that suppress magnetic exchange interaction between grains.
Solution Approach 2:
The patent uses composite materials by combining magnetic crystal grains with non-magnetic grain boundary regions in a granular structure. This composite approach allows the magnetic grains to provide recording functionality while the non-magnetic boundaries reduce magnetic exchange interaction, thereby controlling both transition noise and jitter noise through material composition rather than grain size alone.
2Quantity of substance
If the grain size of the granular-type recording layer is reduced to increase recording density, then the lower limit value of recording bit size is reduced, but the distribution of inverse magnetic field increases causing increase of transition noise and jitter noise
Solution Approach 1:
The patent applies parameter changes by optimizing the size and distribution of non-magnetic grain boundary regions rather than simply reducing magnetic grain size. By adjusting the parameters of the non-magnetic boundaries (width, composition, continuity), the patent achieves fine effective bit size for high recording density while controlling the inverse magnetic field distribution to minimize transition and jitter noise.
3Quantity of substance
If the grain pitch distribution of the perpendicular magnetic recording layer is improved to achieve high-density recording, then recording density is increased, but corrosion resistance may be compromised
Solution Approach 1:
The patent uses an underlayer as an intermediary between the substrate and the perpendicular magnetic recording layer. This underlayer with fine crystal grains serves as a mediator that influences the grain structure of the recording layer, enabling fine grain pitch distribution for high recording density while protecting the recording layer from substrate-related corrosion and maintaining corrosion resistance.
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 configuration enhances the grain pitch distribution of the perpendicular magnetic recording layer, improves corrosion resistance, and maintains good thermal decay characteristics, achieving high-density recording while minimizing noise and signal decay.
Implementation Method 1
a nonmagnetic seed layer which is formed of Ag particles, Ge grain boundaries, and compound X, and continues to the perpendicular magnetic recording layer
Implementation Method 2
improving grain pitch distribution and corrosion resistance by distributing the compound X within the Ag particles and Ge grain boundaries
Implementation Method 3
the magnetic crystal grains are two-dimensionally and physically isolated from each other by the non-magnetic grain boundary region and such a structure achieves reduction in magnetic exchange interaction between the magnetic grains
Data Source
AI summary
According to one embodiment, a magnetic recording medium with high magnetic recording characteristics and improved corrosion resistance is obtained. The magnetic recording medium includes a substrate, an orientation control layer provided on the substrate and made from a Ni alloy or an Ag alloy, a nonmagnetic seed layer provided to be in contact with the orientation control layer, a perpendicular magnetic recording layer containing Fe or Co and Pt as main components. The nonmagnetic seed layer is formed of Ag particles, Ge grain boundaries and a compound X, and the compound X is selected from an oxide, nitride or carbide of aluminum, titanium, chromium, silicon and tantalum and also distributed in both the Ag particles and Ge grain boundaries.