Magnetic Recording Medium Multilayer Exchange Coupling
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Solution Overview
Problem
Current hard disk drive (HDD) systems face challenges in increasing recording density due to low recording and reproduction resolution, and signal-to-noise ratio (SNR) issues in thermally assisted magnetic recording (TAMR) and microwave assisted magnetic recording (MAMR) technologies, particularly with the volume recording method, which struggles with magnetic field gradients and leakage magnetic fields.
Innovation Solution
A magnetic recording and reproducing device with a multilayer structure, comprising a substrate, storage layer, exchange layer, and surface recording layer, where the storage layer and surface recording layer have perpendicular magnetic anisotropy, and the exchange layer facilitates exchange coupling between them, allowing for controlled magnetization transfer and improved recording and reproduction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the magnetic grains are made finer to make the reversed magnetic domain smaller, then the recording density is improved, but the deviation in magnetic properties increases
Solution Approach 1:
The magnetic recording medium is divided into multiple independent recording layers (first recording layer, second recording layer, third recording layer) stacked in the film thickness direction. Each layer contains magnetic grains that can be independently controlled, allowing the system to achieve high recording density without requiring excessively fine magnetic grains in a single layer, thereby reducing magnetic property deviation.
Solution Approach 2:
The invention transitions from two-dimensional in-plane recording to three-dimensional volume recording by stacking multiple recording layers in the film thickness direction. This enables information to be recorded not only in the in-plane direction but also along the film thickness direction, achieving high recording density while maintaining acceptable magnetic grain sizes and reducing magnetic property deviation.
2Quantity of substance
If the number of magnetic grains per bit is decreased to make the reversed magnetic domain smaller, then the recording density is improved, but the signal to noise ratio decreases
Solution Approach 1:
The magnetic recording medium is divided into multiple independent recording layers (first recording layer, second recording layer, third recording layer) stacked in the film thickness direction. Each layer contains magnetic grains that can be independently controlled, allowing the system to achieve high recording density without requiring excessively fine magnetic grains in a single layer, thereby reducing magnetic property deviation.
Solution Approach 2:
The invention transitions from two-dimensional in-plane recording to three-dimensional volume recording by stacking multiple recording layers in the film thickness direction. This enables information to be recorded not only in the in-plane direction but also along the film thickness direction, achieving high recording density while maintaining acceptable magnetic grain sizes and reducing magnetic property deviation.
3Manufacturing precision
If the recording layer is made thin and the flying height is reduced to increase magnetic field gradient, then the recording resolution is improved, but the volume recording performance deteriorates
Solution Approach 1:
The magnetic recording medium is divided into multiple independent recording layers (first recording layer, second recording layer, third recording layer) stacked in the film thickness direction. Each layer contains magnetic grains that can be independently controlled, allowing the system to achieve high recording density without requiring excessively fine magnetic grains in a single layer, thereby reducing magnetic property deviation.
Solution Approach 2:
The invention transitions from two-dimensional in-plane recording to three-dimensional volume recording by stacking multiple recording layers in the film thickness direction. This enables information to be recorded not only in the in-plane direction but also along the film thickness direction, achieving high recording density while maintaining acceptable magnetic grain sizes and reducing magnetic property deviation.
4Measurement precision
If the leakage magnetic field intensity is increased to improve reproduction resolution, then the reproduction resolution is improved, but the signal intensity from underlying layers decreases
Solution Approach 1:
The magnetic recording medium is divided into multiple independent recording layers (first recording layer, second recording layer, third recording layer) stacked in the film thickness direction. Each layer contains magnetic grains that can be independently controlled, allowing the system to achieve high recording density without requiring excessively fine magnetic grains in a single layer, thereby reducing magnetic property deviation.
Solution Approach 2:
A nonmagnetic layer is inserted between the first recording layer and the second recording layer to act as a magnetic field shield. This intermediary layer prevents the leakage magnetic field from the first recording layer from interfering with the second recording layer, thereby maintaining signal intensity while improving reproduction resolution.
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 enhances recording density by maintaining high resolution and SNR, as the magnetization transition region can be accurately transferred between layers, reducing the impact of leakage magnetic fields and improving the overall performance of HDD systems.
Implementation Method 1
the exchange layer facilitates exchange coupling between them, allowing for controlled magnetization transfer
Implementation Method 2
the storage layer and surface recording layer have perpendicular magnetic anisotropy
Data Source
AI summary
A magnetic recording and reproducing device according to an embodiment includes a magnetic recording medium and a controller. The magnetic recording medium includes in sequence a substrate, a storage layer, an exchange layer, and a surface recording layer. The controller executes following steps (1) to (6):(1) magnetically recording first information on the surface recording layer;(2) transferring the first information recorded on the surface recording layer to the storage layer;(3) magnetically recording second information on the surface recording layer;(4) magnetically reproducing the second information from the surface recording layer;(5) transferring the first information recorded on the storage layer to the surface recording layer; and(6) magnetically reproducing the first information transferred to the surface recording layer.