Magnetic Recording Medium Multi-Layer Structure High Density
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Solution Overview
Problem
Current magnetic recording technologies face challenges in increasing recording density while maintaining a high signal-to-noise ratio (SNR) and avoiding positional deviations between data written in different magnetic layers, leading to difficulties in achieving high-speed writing and accurate reproduction.
Innovation Solution
A magnetic recording medium with a multi-layered structure, comprising a soft magnetic underlayer, a non-magnetic intermediate layer, and a recording layer with a first and second magnetic layer, where the second magnetic layer has a higher coercive force than the first and is temporarily reduced when heated, allowing independent recording and reproduction without influencing adjacent layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If recording density is increased by making recording bits finer, then surface recording density is improved, but magnetization minimum volume is reduced causing thermal fluctuation and data loss
Solution Approach 1:
The patent transitions from single-layer recording to multi-layer recording, adding the dimension of layer stacking. By recording data in multiple magnetic layers (first magnetic layer with lower coercivity and second magnetic layer with higher coercivity), the system achieves higher storage density without reducing the volume of individual magnetic particles, thus avoiding thermal fluctuation-induced data loss.
2Quantity of substance
If track density is increased to improve linear recording density, then surface recording density is improved, but pieces of magnetic recording information between adjacent tracks interfere with each other
Solution Approach 1:
The patent segments the magnetic recording layer into multiple magnetically isolated layers. The first magnetic layer and second magnetic layer are separated by a non-magnetic layer, creating distinct magnetic domains that prevent interference between adjacent tracks while maintaining high track density.
3Quantity of substance
If multi-layered structure is used to increase recording density, then storage capacity is doubled, but magnetic field application to upper layer during recording of lower layer causes rewriting
Solution Approach 1:
The patent applies local quality by giving different magnetic layers different coercive forces. The first magnetic layer has lower coercivity for easy writing, while the second magnetic layer has higher coercivity to resist rewriting during the recording process. This local differentiation allows independent recording of each layer without cross-interference.
4Quantity of substance
If heat-assisted recording is used to write in high coercivity layer, then recording density is improved, but coercive force of lower layer decreases causing simultaneous rewriting
Solution Approach 1:
The patent uses dynamics by making the coercive force of the second magnetic layer temperature-dependent. When heated, the coercive force of the second magnetic layer temporarily decreases below that of the first magnetic layer, allowing selective writing in the second layer without affecting the first layer, thus enabling high-density recording while maintaining data integrity.
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 approach enables independent recording on each magnetic layer without positional deviation, doubling the storage capacity and achieving high-speed, accurate writing and reading with improved SNR, thus enhancing recording density and data stability.
Implementation Method 1
a coercive force Hc of the second magnetic layer is larger than that of the first magnetic layer, and the coercive force Hc of the second magnetic layer is smaller than that of the first magnetic layer temporarily when the second magnetic layer is heated
Data Source
AI summary
Provided is a magnetic recording medium including a structure in which at least a soft magnetic underlayer, a non-magnetic intermediate layer, and a magnetic recording layer are sequentially laminated on a non-magnetic substrate, wherein the magnetic recording layer includes a first magnetic layer, a non-magnetic layer, and a second magnetic layer in order from the non-magnetic substrate side, has a structure in which the first magnetic layer and the second magnetic layer are magnetically separated from each other with the non-magnetic layer interposed therebetween, and consists of a plurality of patterns which are magnetically separated from each other, and the coercive force Hc of the second magnetic layer is larger than that of the first magnetic layer, and the coercive force Hc of the second magnetic layer is smaller than that of the first magnetic layer temporarily when the second magnetic layer is heated.