FeRh-FePt Core Shell Nanostructure for High Density Storage
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Solution Overview
Problem
Fully ordered FePt systems are not writable by conventional recording heads due to high coercivity, and thermal fluctuations lead to instability in magnetic recording media, limiting storage density and thermal stability.
Innovation Solution
Magnetic coupling of FeRh with FePt nanoparticles, where FeRh's antiferromagnetic to ferromagnetic transition is exploited to lower the coercivity and increase thermal stability, allowing for the use of FeRh-FePt nanocomposites as ultra-high density recording media, enabling writing with conventional heads and enhancing thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fully ordered FePt systems are used to increase thermal stability, then thermal stability is improved, but coercivity becomes too high for conventional recording heads to write
Solution Approach 1:
The patent creates a core-shell nanocomposite structure where FePt nanoparticles (providing thermal stability through high magnetocrystalline anisotropy) are combined with FeRh shell material (providing magnetically soft properties with lower coercivity). This composite structure enables the media to be written by conventional recording heads while maintaining thermal stability at high storage densities.
2Quantity of substance
If storage density is increased to improve capacity, then storage density is improved, but thermal fluctuations cause instability in the magnetic recording media
Solution Approach 1:
The patent utilizes the temperature-dependent magnetic properties of FeRh, specifically its antiferromagnetic to ferromagnetic transition around 350K. By exploiting this parameter change with temperature, the FeRh shell modifies the overall magnetic characteristics of the nanocomposite, enabling thermal stability at high storage densities where conventional media would exhibit superparamagnetic effects.
3Ease of operation
If conventional recording heads are used to maintain compatibility, then ease of operation is improved, but write field strength is insufficient for high coercivity media
Solution Approach 1:
The patent applies the local quality principle by creating a core-shell structure where different regions have different magnetic properties. The FePt core provides high anisotropy for thermal stability, while the FeRh shell provides magnetically soft characteristics with lower coercivity. This spatial differentiation of magnetic properties allows conventional recording heads to write the media effectively.
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 FeRh-FePt nanocomposite reduces coercivity, allowing for conventional recording head compatibility and increases thermal stability, overcoming write field limitations and thermal instability issues in magnetic recording.
Implementation Method 1
FeRh's antiferromagnetic to ferromagnetic transition is exploited to lower the coercivity
Implementation Method 2
increases thermal stability, overcoming write field limitations and thermal instability issues in magnetic recording
Data Source
AI summary
Disclosed herein are methods and processes for making FeRh/FePt nanostructures and the use of these FeRh—FePt nanostructures as a magnetic recording media.