Patterned Substrate Grain Growth Control
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Solution Overview
Problem
The miniaturization of magnetic grains in magnetic storage media is limited by the superparamagnetic effect, leading to data corruption and non-uniform grain size distribution, which degrades recording performance and increases noise in high-density recording.
Innovation Solution
A patterned magnetic storage medium is created with a substrate having physical or chemical patterns that guide the growth of magnetic grains, using a non-magnetic segregant to form boundaries around each grain, promoting uniformity and reducing random nucleation sites, thereby enhancing grain size distribution and recording performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If magnetic grains are miniaturized to increase data density, then storage capacity is improved, but the superparamagnetic effect causes spontaneous magnetization flipping and data corruption
Solution Approach 1:
The patent transitions from longitudinal recording (magnetization in-plane) to perpendicular recording (magnetization out-of-plane). This dimensional change allows grains to be miniaturized without suffering from the superparamagnetic effect, as the out-of-plane magnetization configuration provides enhanced thermal stability while maintaining high data density.
Solution Approach 2:
The patent changes the magnetization orientation parameter from in-plane to out-of-plane direction. This parameter change fundamentally alters the thermal stability characteristics of the magnetic grains, enabling miniaturization without data corruption by modifying the energy barrier against spontaneous magnetization flipping.
2Ease of manufacture
If conventional sputtering processes are used to form magnetic grains, then manufacturing simplicity is maintained, but grain size non-uniformity occurs which degrades recording performance
Solution Approach 1:
The patent applies a preliminary topographical pattern to the substrate before magnetic material deposition. This pre-formed pattern serves as a template that guides subsequent grain growth, ensuring uniform grain size distribution. The patterned substrate prepares the surface in advance to receive and organize the magnetic material into uniformly spaced grains.
Solution Approach 2:
The patent introduces spatially varying topographical features (protrusions and recesses) at different locations on the substrate. These local quality variations create corresponding variations in magnetic material deposition and grain growth, resulting in uniform grain size distribution across the entire substrate while maintaining manufacturing simplicity.
3Device complexity
If random nucleation is used to form magnetic grains, then process complexity is minimized, but zig-zag boundaries and random grain boundary thickness occur which complicate track formation
Solution Approach 1:
The patent performs preliminary patterning of the substrate with regular geometric features (protrusions and recesses) before magnetic material deposition. This pre-established regular pattern replaces random nucleation, guiding magnetic grains to form at predetermined locations with uniform spacing and regular boundaries, thereby simplifying subsequent track formation.
Solution Approach 2:
The patent divides the substrate surface into distinct segmented regions (protrusions and recesses) with well-defined boundaries. This segmentation approach organizes the magnetic grain formation process, ensuring that grains nucleate and grow in controlled, discrete locations rather than randomly, resulting in regular grain boundaries and uniform track geometry.
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 achieves more uniform grain size and improved recording performance by controlling grain growth through substrate patterning, reducing the superparamagnetic effect and enhancing data density without increasing noise.
Implementation Method 1
The non-magnetic material may be a segregant that forms a boundary area around a perimeter of each of a plurality of magnetic grains. The segregant, denoted as M in the above formula, is a material with low surface energy and low affinity.
Implementation Method 2
A patterned magnetic storage medium is created with a substrate having physical or chemical patterns that guide the growth of magnetic grains
Implementation Method 3
During the sputtering process of the magnetic film, the low-surface-energy segregant comes out of the sputtering solution and moves toward the grain boundary to form a boundary area for each grain.
Data Source
AI summary
According to one embodiment, a patterned magnetic storage medium is disclosed herein. The magnetic storage medium includes a pattern formed on a substrate. The pattern includes at least a first and second feature and an edge defined between the first and second features. Additionally, the magnetic storage medium includes a magnetic layer formed on the pattern. The magnetic layer includes grains separated by a non-magnetic segregant boundary. The segregant boundary is positioned above the edge of the pattern.