MAMR Head Assist Layer for Thermal Stability
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Solution Overview
Problem
Conventional magnetic storage devices face challenges in achieving high recording densities due to thermal demagnetization and the 'trilemma' of narrower track widths, which hinder the development of high recording densities, especially when using conventional technologies.
Innovation Solution
The implementation of a magnetic storage device with a microwave-assisted magnetic recording (MAMR) head that includes a spin torque oscillator (STO) and a magnetic recording medium with a recording layer and an assist layer, where the assist layer is positioned closer to the air bearing surface than the recording layer, comprising Co, Pt, and an oxide, with a smaller anisotropic magnetic field than the recording layer, to effectively control magnetic characteristics and enhance recording performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size of crystal grains is decreased to increase recording density, then recording density is improved, but thermal demagnetization occurs and recording magnetization becomes unstable
Solution Approach 1:
The invention changes the magnetic anisotropy parameter by introducing a assist layer with high magnetic anisotropy field (Hk) adjacent to the recording layer. This modifies the energy barrier for magnetization reversal, preventing thermal demagnetization while maintaining fine crystal grain sizes for high recording density.
Solution Approach 2:
The invention uses a composite structure consisting of a recording layer with fine crystal grains and a assist layer with high magnetic anisotropy. This composite material combination achieves both high recording density (through fine grains) and thermal stability (through the high Hk assist layer).
2Quantity of substance
If the track width in the magnetic head is narrowed to achieve high recording density, then recording density is improved, but the recording magnetic field of the magnetic head becomes smaller
Solution Approach 1:
The invention changes the magnetic field parameter by introducing a microwave magnetic field oscillation element that generates a time-varying magnetic field. This microwave field assists the main magnetic head in achieving sufficient recording field strength even with narrower track widths, thereby enabling high recording density without sacrificing magnetic field strength.
Solution Approach 2:
The invention employs periodic microwave frequency magnetic field oscillation to assist the recording process. The periodic oscillation at microwave frequencies modulates the magnetic anisotropy of the recording layer, reducing the energy barrier for magnetization reversal and enabling effective recording with narrower tracks.
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 enables satisfactory recording characteristics and high recording densities by appropriately controlling the magnetic characteristics of the medium, allowing for a high assist effect from the microwave magnetic field, thereby overcoming thermal demagnetization and track width limitations.
Implementation Method 1
Ferro-magnetic resonance (FMR) occurs when the frequency of the microwave magnetic field matches the resonance frequency of the magnetization of the medium and the spin precession is further activated.
Implementation Method 2
Ferro-magnetic resonance (FMR) occurs when the frequency of the microwave magnetic field matches the resonance frequency of the magnetization of the medium and the spin precession is further activated.
Implementation Method 3
MAMR incorporates a microwave magnetic field oscillation element into the recording head and records by superimposing a microwave magnetic field on the recording magnetic field of the head.
Data Source
AI summary
In one embodiment, a magnetic storage device includes at least one microwave assisted magnetic recording (MAMR) head, each MAMR head including a spin torque oscillator (STO), a magnetic recording medium, a drive mechanism for passing the magnetic medium over the at least one MAMR head, and a controller electrically coupled to the at least one MAMR head for controlling operation of the at least one MAMR head, wherein the magnetic recording medium includes a recording layer positioned directly or indirectly above a substrate and an assist layer positioned above the recording layer, wherein the recording layer includes at least Co, Pt, and an oxide or oxygen, wherein the assist layer is positioned closer to the at least one MAMR head and includes at least Co and Pt, and wherein at least a portion of the recording layer has a smaller anisotropic magnetic field than the assist layer.