Perpendicular Magnetic Recording Medium Layer Structure
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Solution Overview
Problem
Conventional magnetic recording media face challenges in simultaneously improving recording capacity and recording and reproducing characteristics, particularly due to the overlap of servo information and data regions, which affects signal-to-noise ratio and thermal stability.
Innovation Solution
A magnetic recording medium with a stacked structure comprising an orientation control layer, a lower recording layer with a higher coercivity, and an upper recording layer, where the lower recording layer has a granular structure with Co, Cr, and Pt magnetic particles and an oxide, and the upper recording layer has a non-granular structure, enhancing signal readability and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single perpendicular recording layer is used to increase recording density, then recording capacity is improved, but signal-to-noise ratio deteriorates due to overlap of servo information and data regions
Solution Approach 1:
The recording layer is divided into two separate perpendicular recording layers (first and second layers) with different coercivity values. The first layer has higher coercivity and is used for recording data, while the second layer has lower coercivity and is used for recording servo information. This segmentation allows independent optimization of recording parameters for each function, improving signal-to-noise ratio while maintaining high recording capacity.
2Quantity of substance
If recording density is increased to improve recording capacity, then more information can be stored, but thermal stability of recorded bits deteriorates
Solution Approach 1:
Different regions of the recording medium are assigned different coercivity values to optimize local performance. The first recording layer with higher coercivity provides better thermal stability for data bits, while the second recording layer with lower coercivity enables easier writing of servo information. This local differentiation of magnetic properties allows high recording density to be achieved without compromising thermal stability of stored data.
3Device complexity
If conventional single-layer structure is used to simplify device complexity, then manufacturing is easier, but inability to simultaneously improve recording capacity and recording/reproducing characteristic arises
Solution Approach 1:
The patent employs a composite structure consisting of two perpendicular recording layers with different coercivity characteristics. This composite layer structure enables simultaneous optimization of recording capacity and recording/reproducing characteristics, overcoming the limitations of conventional single-layer designs while maintaining compatibility with existing manufacturing 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
This configuration improves the signal-to-noise ratio and thermal stability, allowing for increased recording capacity and high-density information recording by separating servo information and data regions effectively.
Implementation Method 1
The magnetic storage apparatus may be provided with the so-called perpendicular magnetic recording medium in which an axis of easy magnetization within a recording layer is mainly oriented in a perpendicular direction
Implementation Method 2
a magnetic head configured to read and write information with respect to a perpendicular magnetic layer formed by the upper recording layer and the lower recording layer of the magnetic recording medium
Data Source
AI summary
A magnetic recording medium may include a stacked structure of orientation control, lower recording, intermediate, and upper recording layers. The lower recording layer has a coercivity higher than that of the upper recording layer. The lower recording layer includes a first layer with a granular structure that includes magnetic particles including Co, Cr, and Pt, and an oxide covering a periphery of the magnetic particles, and a second layer with a non-granular structure that includes magnetic particles including Co, Cr, and Pt. The lower recording layer includes columnar crystals continuous with crystal particles forming the orientation control layer in a stacking direction of the stacked structure.