Low-Coupling Oxide Media for Perpendicular Magnetic Recording
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Solution Overview
Problem
Existing magnetic recording media face challenges in achieving high capacity storage due to limitations in magnetization orientation and coupling between magnetic domains, particularly in longitudinal configurations, which hinder efficient data storage and retrieval.
Innovation Solution
Incorporating a low saturation magnetization layer in perpendicular magnetic recording media structures to achieve weak uniform direct exchange coupling between magnetic grains, allowing for controlled magnetization and improved recording properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If perpendicular recording media are fabricated with polycrystalline CoCr alloy or CoPt-oxide alloy film, then magnetization forms in a direction perpendicular to the surface of the magnetic layer, but magnetic interaction between adjacent ferromagnetic domains is strong due to proximity of Co-rich areas
Solution Approach 1:
The magnetic layer is segmented into Co-rich ferromagnetic areas and Cr or oxide rich non-magnetic areas. The non-magnetic areas act as separators that divide the continuous ferromagnetic regions into discrete domains, reducing magnetic interaction between adjacent domains while maintaining perpendicular magnetization in the Co-rich regions.
Solution Approach 2:
Cr or oxide rich non-magnetic areas are introduced as intermediary layers between Co-rich ferromagnetic domains. These intermediary non-magnetic regions attenuate the magnetic interaction between adjacent ferromagnetic domains, allowing independent domain behavior while preserving the perpendicular magnetization structure.
2Productivity
If longitudinal configuration is used with in-plane anisotropy, then magnetization forms in a direction in a plane parallel to the surface, but storage capacity is limited compared to perpendicular configuration
Solution Approach 1:
The invention transitions from longitudinal (in-plane) magnetization to perpendicular magnetization by changing the dimension of magnetization orientation. The magnetic anisotropy is engineered so that the easy axis of magnetization is perpendicular to the film plane rather than in-plane, enabling higher storage capacity through out-of-plane magnetic domain configuration.
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 implementation of a low saturation magnetization layer in perpendicular media structures enhances recording performance by reducing exchange coupling, enabling higher storage capacity and improved magnetization alignment, as demonstrated by Monte Carlo simulations and experimental data.
Implementation Method 1
Incorporating a low saturation magnetization layer in perpendicular magnetic recording media structures to achieve weak uniform direct exchange coupling between magnetic grains
Implementation Method 2
Each domain contains parallel atomic moments and is magnetized to saturation, but the directions of magnetization of different domains are not necessarily parallel
Implementation Method 3
When a magnetic field is applied, the domains most nearly parallel to the direction of the applied field grow in size at the expense of the others. This is called boundary displacement of the domains or domain growth
Data Source
AI summary
A low-coupling perpendicular magnetic recording media comprising a magnetic storage layer and at least one low saturation magnetization layer. The magnetic storage layer has a saturation magnetization between about 400-900 emu/cm3 and the at least one low saturation magnetization layer has a saturation magnetization below that of the magnetic storage layer.